user1513: Many people suggest tactical exercises as the best form of study for this purpose but I find that it only attacks the problem from one dimension (not making the strongest in a position). Analyzing my own games I find that I'm much more likely to lose a game by making a dumb blunder rather than missing a winning combination, so solving more chess puzzles doesn't seem very effective at improving that. Any other forms of exercise that could help with this?

user12540: The shortest ways to prevent Blunders is 

Look for which Opponent's Piece is coming more into your Territory or can cross half of the Board . It is also one way of finding the most aggressive reply of your opponent .
When you move your Piece make sure you check the Placement of your Opponents Pieces . It would be worth if you can start with the most Worthy Piece from Q/R/B/K/Pawn.
Make sure you play Blitz/Bullet Chess and there your Objective would not be to win the game but to prevent any Blunders . Make sure that you do an Anti Blunder Check before you move your Piece.

I saw this Video from one of my Chess Teachers GM Igor Smirnov . Here is the link from his Youtube channel . I hope this would be of some help to you.
How to Eliminate Blunders - 1
How to Eliminate Blunders - 2

user7657: This answer may be redundant by now, but when I was regularly playing tournament chess, I wrote down 2 pieces of advice for myself in advance on a 3x5 card (which is probably illegal now).  They were "Anticipate" and "No Blitz". since most of my blunders stemmed from not checking my opponent's potential replies and from moving too quickly before I had double checked my own intended move.  This worked pretty well, for me at any rate. 

user3872: Here's an interesting alternative. Play bullet chess. Bullet chess is all about seeing your opponents threats and dumb blunders. It helps you familiarize with the pieces and how they move and helps you to avoid blunders and see threats quickly. Bullet also improves your ability to cope in time pressure, and that is where most blunders happen. Of course, bullet chess should not be the main means of improvement, but it does improve one's abilities during time pressure.

user18273: "Blunders are nothing but tactics you didn't saw from your opponent's side"
I will tell you my story and my improvement over this problem of blundering.
I was blundering and blundering very badly even after I started seriously studying chess. This was particularly frustrating as I was spending time studying endgames themes, positional ideas in middle games and the next day I am losing my queen to a pin in 12th move.
What did I do?

I noted down all the key tactical themes and kept an eye for them in every single move of my opponent.

Hanging pieces | Pin | Fork | Skewer (X-ray attack) | Discovered Attack | Removing the defender | Trapping pieces | Decoy | Back Rank Weakness.

I found out the tactics which I was more susceptible to.

I found that I was mostly falling for pins, Interestingly only for pins along diagonals but never for pins along ranks or files.
I saw I am falling many times for the "removing the defender" tactic. 
one other common thing I noticed was that I sometimes did the mistake of blocking my own defender and end up hanging one piece.
(90% of my blunders were one of the above three)

Avoid impulsive moves

Whenever I had 2-3 candidate moves in a position and I reject the first choice after some analysis I had an impulsive tendency to play the second choice without thinking much. This was also one of the major parts of the game where I blundered most.

Decided to play next 100 games with only one objective - "Don't make any blunder"

To force myself to do all the above, 

I had to play slower time control games

So I shifted from blitz to 15|10 rapid games in online sites.
I was totally fine with losing, My only intention was to have 100 games where I didn't make any stupid blunder. 
Epilogue
Yes, I had my 100 games without any blunder and that was a confidence booster. These 100 games helped me fix my eyes for the tactics I was missing, And I am making far fewer blunders these days (even in blitz games).
One Last suggestion:
chess.com offers an option to practice for selected tactical themes under the puzzles sessions and you have an option to choose from a wide variety of themes.

user224: Practice a different sort of tactics!
According to chess teacher and author Dan Heisman, traditional tactics puzzles (e.g. "Mate in 3" puzzles) present you with a situation in which you are trying to exploit a mistake your opponent has made. While this may help you recognize some mistakes, it doesn't train your brain to look for mistakes you have made or are about to make. Thus Mr. Heisman has written a book titled Is Your Move Safe? which shows positions and asks you to determine whether a move (or set of moves) is safe to make. 
After a disappointing result at my last tournament - in which I blundered away two games in which I had clear advantages (up a rook in one of them) - I bought this book. While I'm only into the second chapter of puzzles, I like it so far. Unfortunately, things being what they are right now (we are in the midst of the COVID-19 pandemic as I type this), I have not yet had an opportunity in a tournament setting to see if it is helping.
Heisman has another book titled Looking For Trouble. I do not have it (yet). However, from the write up about it, the emphasis seems to be similar, although more aimed at identifying and defending against threats your opponent has.

user1105: From my own experience, and i'm not a highly rated player or anything like that, the best way to eliminate blunders is not to play aggressive openings, defensive players commit less blunders, they may lose because they don't have the space advantage but they don't make blunders as much as aggressive players.
Why do players make blunders usually?

They start to attack without counting how many defenders are there.
They exchange pieces trying to open up the game or to counter an
attack, without counting how many defenders they have.
They start to attack without securing the king safety.
They rush into the middle game, without having completed developing
their pieces.
They rush into the end game, trying to finish the opponent too early.
They play complex positions, they don't even understand.

From my experience, the majority of the blunders is simply because the players fail to count the defenders or because they rush to attack. Of course failing to understand your opponent opening will result in blunders but this is usually isn't the main cause with average players.
So take your time, develop all the pieces, try to control the pace of the game, space advantage is so important but don't rush it, and keep your game simple, don't play positions you are not familiar with.

user478: 
always ask yourself what is your opponent trying to achieve with his
last move.
make your move in your head without submitting it, then find the best reply for your opponent (if he can do something serious, undo your move and try to stop it, if it is too late to stop it, then consider resigning).

This will greatly cut down the direct blunders. However, as you play with stronger opponents, you will need to do #2 several times to see more than 1 move into the future, but it gets pretty hard depending on how well you calculate and what time settings you play with.
Also, as a bonus, study lots of tactics, and learn how they can be used against you. The most common ones I think are:

having overloaded pieces
leaving pieces hanging
not seeing that he just did something sneaky like a discovered attack or preparing a fork

But one can never do enough calculations. It would be unfair to say white blundered in this game.

user657: Blumenfeld's Rule: Once you have decided on a move, stop thinking about your analysis and look at just that move as if you were reading it in a book, or having it played against you.
The "full monte" on this is that you write the move on your scoresheet, but some players started using this to excuse taking notes during a game (writing 4 and 5 moves down before playing one) so it's now illegal in USCF events. But just fixing it afresh in your mind will be almost the same.

user935: Personally I have noticed many of my worst blunders seem to come from trying to play on a square I don't control.  Basically I'll get so focused on trying to attack a particular target that I will hang a piece trying to get at it.  If I see myself starting to do that, I'll stare at the square I'm likely to blunder on and tell myself "NO" (not out loud unless I am trying to freak my opponent out...) or imagine a big red X over it.  Seems to help a little.

user1549: I see a lot of responses recommending looking at the game from the opponent's point of view, and I can see why, ever since I started adopting this technique in my games. It really works.
Until very recently, I always used to look at my game from my view, my plan, my killer tactic, my decisive blow -- which, theoretically, if implemented perfectly should be sufficient. But recently one of the approaches I use is to analyze every move my opponent makes with a "Okay, so what's his plan?" or "Why did he do that?" before I start working out my plan. If I see his idea easily and feel its not threatening enough, I proceed with my plan.
If I can't seem to find his idea easily, I conclude that either I need to look harder because there's a killer attack coming on or that it's a weak/aimless move. I do dismiss activating pieces, like I used to do earlier, as aimless moves, but instead look for ways to stifle this. The downside of this approach is that you have be good at time management, since first working out your opponent's plan, assessing the threat, and then formulating your own plan usually takes more time than if you were just thinking from your perspective.

user1382: Tactics cover a broad area that doesn't only concern mistakes that your opponents make. The pattern recognition faculties that you improve through tactics also help you realize the blunders that you yourself make. I don't recommend trying to change your style of play at all - I tell my students that at an early level, one of the most important things is to not hang pieces and to take advantage of your opponents' hanging pieces. Thus, before you make your move, specifically ask yourself if you see any potential tactics for your opponent. Likewise, do the same after every single opponent's move. 

user3575: Chuzhakin's System is written in 70 PDF pages. 
video:Chuzhakin's System intro
It has 18 Rules to find so called "Hazardous Elements" - HE.
Before making the move which we selected we need to check for blunders. All be blunders means that we do not see any HE or we do not see a method how to use HE (about 20 typical methods descirbed in the System).
Thinking algorithm to avoid blunders is in the scheme.


user72: As a human you are intrinsically self biased. This is hypothesized to be an evolutionary adaption and it is impossible to suppress it, or more accurately to think objectively about yourself. Until you are accurately able to gauge and control the degree to which your self-bias affects your own thinking, this will be the primary cause of blunders in your chess games.
How can you be so certain that self-bias is the primary cause of blunders?
Well, let's examine the definition of a blunder more closely:

Especially among amateur and novice players, blunders often occur because of a faulty thought process where they do not consider the opponent's forcing moves. In particular, checks, captures, and threats need to be considered at each move. Neglecting these possibilities leaves a player vulnerable to simple tactical errors.

The fragment

blunders often occur because of a faulty thought process where they do not consider the opponent's forcing moves.

implies that blunders occur because a lack of diligence on the side of he who blunders. Excluding time-control troubles, there are only a few remaining possible reasons for not considering the best moves of your opponent and most of them deal with the self-bias:

Too focused on attacking to see that your opponent has the stronger attack and you are better served by defending
Fail to evaluate a tactic to a quiescent position because you feel like you're better than your opponent so it must work out in your favour
You are several points up in material, you don't have to work any more, your opponent should just keel over and give you your well-earned victory, why must they insist on fighting on?

How can I overcome this?
Short answer: you can't. By definition, it's part of you, unless you are born with some weird genetic mutation. Luckily, there are all sorts of ways to "trick" your brain into avoiding a thought process that is controlled by the self-bias. My favorite trick is simplest of all and it comes from an old adage:

Before you judge someone walk a mile in their shoes, that way you are a mile away and you have their shoes :)

To make it clear, what I mean is simply look at the game from your opponen'ts perspective, and search for that "killer" move to win the game, but on his side. That way, you can spot it and direct the game away from it.

user97: If you want to avoid "dumb blunders" - i.e. just dropping a piece you've left hanging on the other side of the board - a simple method is to take an inventory of the position before you do anything else on each move. Checking which of your pieces are attacked and which of your pieces are hanging would be a good start. The brain will catalogue this information into 8x8-grid punch-card type patterns in your head that act as a warning system against stupid errors.
It can however be surprisingly difficult to take a regimented approach like this even if on the surface it seems quite a trivial task to complete at the start of each of your moves. The brain has a tendency to immediately want to investigate interesting lines and will wander sometimes never to return. Even harder if you're an older player who has never applied such discipline.
But if you stick at it over time it becomes second nature and you just see better and don't blunder as much.

1513: <p>Many people suggest tactical exercises as the best form of study for this purpose but I find that it only attacks the problem from one dimension (not making the strongest in a position). Analyzing my own games I find that I'm much more likely to lose a game by making a dumb blunder rather than missing a winning combination, so solving more chess puzzles doesn't seem very effective at improving that. Any other forms of exercise that could help with this?</p>
 12540: <p>The shortest ways to prevent Blunders is </p>

<ol>
<li>Look for which Opponent's Piece is coming more into your Territory or can cross half of the Board . It is also one way of finding the most aggressive reply of your opponent .</li>
<li>When you move your Piece make sure you check the Placement of your Opponents Pieces . It would be worth if you can start with the most Worthy Piece from Q/R/B/K/Pawn.</li>
<li>Make sure you play Blitz/Bullet Chess and there your Objective would not be to win the game but to prevent any Blunders . Make sure that you do an Anti Blunder Check before you move your Piece.</li>
</ol>

<p>I saw this Video from one of my Chess Teachers GM Igor Smirnov . Here is the link from his Youtube channel . I hope this would be of some help to you.</p>

<p><a href="http:////https://www.youtube.com/watch?v=_N0E0eahWnQ" rel="nofollow noreferrer">How to Eliminate Blunders - 1</a></p>

<p><a href="https://www.youtube.com/watch?v=xASlcNhMXwg" rel="nofollow noreferrer">How to Eliminate Blunders - 2</a></p>
 7657: <p>This answer may be redundant by now, but when I was regularly playing tournament chess, I wrote down 2 pieces of advice for myself in advance on a 3x5 card (which is probably illegal now).  They were "Anticipate" and "No Blitz". since most of my blunders stemmed from not checking my opponent's potential replies and from moving too quickly before I had double checked my own intended move.  This worked pretty well, for me at any rate. </p>
 3872: <p>Here's an interesting alternative. Play bullet chess. Bullet chess is all about seeing your opponents threats and dumb blunders. It helps you familiarize with the pieces and how they move and helps you to avoid blunders and see threats quickly. Bullet also improves your ability to cope in time pressure, and that is where most blunders happen. Of course, bullet chess should not be the main means of improvement, but it does improve one's abilities during time pressure.</p>
 18273: <p><em>"Blunders are nothing but tactics you didn't saw from your opponent's side"</em></p>

<p>I will tell you my story and my improvement over this problem of blundering.</p>

<p>I was blundering and blundering very badly even after I started seriously studying chess. This was particularly frustrating as I was spending time studying endgames themes, positional ideas in middle games and the next day I am losing my queen to a pin in 12th move.</p>

<h2>What did I do?</h2>

<ul>
<li><strong>I noted down all the key tactical themes and kept an eye for them in every single move of my opponent.</strong></li>
</ul>

<p>Hanging pieces | Pin | Fork | Skewer (X-ray attack) | Discovered Attack | Removing the defender | Trapping pieces | Decoy | Back Rank Weakness.</p>

<ul>
<li><strong>I found out the tactics which I was more susceptible to.</strong></li>
</ul>

<p>I found that I was mostly falling for pins, Interestingly only for pins along diagonals but never for pins along ranks or files.</p>

<p>I saw I am falling many times for the "removing the defender" tactic. </p>

<p>one other common thing I noticed was that I sometimes did the mistake of blocking my own defender and end up hanging one piece.</p>

<p>(90% of my blunders were one of the above three)</p>

<ul>
<li><strong>Avoid impulsive moves</strong></li>
</ul>

<p>Whenever I had 2-3 candidate moves in a position and I reject the first choice after some analysis I had an impulsive tendency to play the second choice without thinking much. This was also one of the major parts of the game where I blundered most.</p>

<ul>
<li><strong>Decided to play next 100 games with only one objective - "Don't make any blunder"</strong></li>
</ul>

<p>To force myself to do all the above, </p>

<blockquote>
  <p>I had to play slower time control games</p>
</blockquote>

<p>So I shifted from blitz to 15|10 rapid games in online sites.</p>

<p>I was totally fine with losing, My only intention was to have 100 games where I didn't make any stupid blunder. </p>

<h2>Epilogue</h2>

<p>Yes, I had my 100 games without any blunder and that was a confidence booster. These 100 games helped me fix my eyes for the tactics I was missing, And I am making far fewer blunders these days (even in blitz games).</p>

<p><strong>One Last suggestion:</strong></p>

<p><a href="https://www.chess.com/" rel="nofollow noreferrer">chess.com</a> offers an option to practice for selected tactical themes under the puzzles sessions and you have an option to choose from a wide variety of themes.</p>
 224: <p>Practice a different sort of tactics!</p>

<p>According to chess teacher and author Dan Heisman, traditional tactics puzzles (e.g. "Mate in 3" puzzles) present you with a situation in which you are trying to exploit a mistake your opponent has made. While this may help you recognize some mistakes, it doesn't train your brain to look for mistakes you have made or are about to make. Thus Mr. Heisman has written a book titled <strong><em><a href="https://www.danheisman.com/is-your-move-safe.html" rel="nofollow noreferrer">Is Your Move Safe?</a></em></strong> which shows positions and asks you to determine whether a move (or set of moves) is safe to make. </p>

<p>After a disappointing result at my last tournament - in which I blundered away two games in which I had clear advantages (up a rook in one of them) - I bought this book. While I'm only into the second chapter of puzzles, I like it so far. Unfortunately, things being what they are right now (we are in the midst of the COVID-19 pandemic as I type this), I have not yet had an opportunity in a tournament setting to see if it is helping.</p>

<p>Heisman has another book titled <a href="https://rads.stackoverflow.com/amzn/click/com/B00JVAW5OE" rel="nofollow noreferrer" rel="nofollow noreferrer"><strong><em>Looking For Trouble</em></strong></a>. I do not have it (yet). However, from the write up about it, the emphasis seems to be similar, although more aimed at identifying and defending against threats your opponent has.</p>
 1105: <p>From my own experience, and i'm not a highly rated player or anything like that, the best way to eliminate blunders is not to play aggressive openings, defensive players commit less blunders, they may lose because they don't have the space advantage but they don't make blunders as much as aggressive players.</p>

<p><strong>Why do players make blunders usually?</strong></p>

<ol>
<li>They start to attack without counting how many defenders are there.</li>
<li>They exchange pieces trying to open up the game or to counter an
attack, without counting how many defenders they have.</li>
<li>They start to attack without securing the king safety.</li>
<li>They rush into the middle game, without having completed developing
their pieces.</li>
<li>They rush into the end game, trying to finish the opponent too early.</li>
<li>They play complex positions, they don't even understand.</li>
</ol>

<p>From my experience, the majority of the blunders is simply because the players fail to count the defenders or because they rush to attack. Of course failing to understand your opponent opening will result in blunders but this is usually isn't the main cause with average players.</p>

<p>So take your time, develop all the pieces, try to control the pace of the game, space advantage is so important but don't rush it, and keep your game simple, don't play positions you are not familiar with.</p>
 478: <ol>
<li>always ask yourself what is your opponent trying to achieve with his
last move.</li>
<li>make your move in your head without submitting it, then find the best reply for your opponent (if he can do something serious, undo your move and try to stop it, if it is too late to stop it, then consider resigning).</li>
</ol>

<p>This will greatly cut down the <em>direct blunders</em>. However, as you play with stronger opponents, you will need to do #2 several times to see more than 1 move into the future, but it gets pretty hard depending on how well you calculate and what time settings you play with.</p>

<p>Also, as a bonus, study lots of tactics, and learn how they can be used against you. The most common ones I think are:</p>

<ul>
<li>having overloaded pieces</li>
<li>leaving pieces hanging</li>
<li>not seeing that he just did something sneaky like a discovered attack or preparing a fork</li>
</ul>

<p>But one can never do enough calculations. It would be unfair to say white blundered <a href="http://www.chess.com/forum/view/more-puzzles/win-material-in-this-position" rel="nofollow noreferrer">in this game</a>.</p>
 657: <p>Blumenfeld's Rule: Once you have decided on a move, stop thinking about your analysis and look at just that move as if you were reading it in a book, or having it played against you.</p>

<p>The "full monte" on this is that you write the move on your scoresheet, but some players started using this to excuse taking notes during a game (writing 4 and 5 moves down before playing one) so it's now illegal in USCF events. But just fixing it afresh in your mind will be almost the same.</p>
 935: <p>Personally I have noticed many of my worst blunders seem to come from trying to play on a square I don't control.  Basically I'll get so focused on trying to attack a particular target that I will hang a piece trying to get at it.  If I see myself starting to do that, I'll stare at the square I'm likely to blunder on and tell myself "NO" (not out loud unless I am trying to freak my opponent out...) or imagine a big red X over it.  Seems to help a little.</p>
 1549: <p>I see a lot of responses recommending looking at the game from the opponent's point of view, and I can see why, ever since I started adopting this technique in my games. It really works.</p>

<p>Until very recently, I always used to look at my game from my view, my plan, my killer tactic, my decisive blow -- which, theoretically, if implemented perfectly should be sufficient. But recently one of the approaches I use is to analyze every move my opponent makes with a "Okay, so what's his plan?" or "Why did he do that?" before I start working out my plan. If I see his idea easily and feel its not threatening enough, I proceed with my plan.</p>

<p>If I can't seem to find his idea easily, I conclude that either I need to look harder because there's a killer attack coming on or that it's a weak/aimless move. I do dismiss activating pieces, like I used to do earlier, as aimless moves, but instead look for ways to stifle this. The downside of this approach is that you have be good at time management, since first working out your opponent's plan, assessing the threat, and then formulating your own plan usually takes more time than if you were just thinking from your perspective.</p>
 1382: <p>Tactics cover a broad area that doesn't only concern mistakes that your opponents make. The pattern recognition faculties that you improve through tactics also help you realize the blunders that you yourself make. I don't recommend trying to change your style of play at all - I tell my students that at an early level, one of the most important things is to not hang pieces and to take advantage of your opponents' hanging pieces. Thus, before you make your move, specifically ask yourself if you see any potential tactics for your opponent. Likewise, do the same after every single opponent's move. </p>
 3575: <p>Chuzhakin's System is written in 70 <a href="http://www.neoneuro.com/downloads/chuzhakinssystem.pdf" rel="noreferrer">PDF pages</a>. 
video:<a href="http://www.youtube.com/watch?v=iE6rce7el-U" rel="noreferrer">Chuzhakin's System intro</a></p>

<p>It has 18 Rules to find so called "Hazardous Elements" - HE.
Before making the move which we selected we need to check for blunders. All be blunders means that we do not see any HE or we do not see a method how to use HE (about 20 typical methods descirbed in the System).
Thinking algorithm to avoid blunders is in the scheme.
<img src="https://i.stack.imgur.com/pRtdD.png" alt="thinking algorithm"></p>
 72: <p>As a human you are <a href="http://en.wikipedia.org/wiki/Self-serving_bias" rel="noreferrer">intrinsically self biased</a>. This is hypothesized to be an evolutionary adaption and it is impossible to suppress it, or more accurately to think objectively about yourself. Until you are accurately able to gauge and control the degree to which your self-bias affects your own thinking, this will be the primary cause of blunders in your chess games.</p>
<h2>How can you be so certain that self-bias is the primary cause of blunders?</h2>
<p>Well, let's examine the definition of a blunder more closely:</p>
<blockquote>
<p>Especially among amateur and novice players, blunders often occur because of a faulty thought process where they do not consider the opponent's forcing moves. In particular, checks, captures, and threats need to be considered at each move. Neglecting these possibilities leaves a player vulnerable to simple tactical errors.</p>
</blockquote>
<p>The fragment</p>
<blockquote>
<p>blunders often occur because of a faulty thought process where they do not consider the opponent's forcing moves.</p>
</blockquote>
<p>implies that blunders occur because a lack of diligence on the side of he who blunders. Excluding time-control troubles, there are only a few remaining possible reasons for not considering the best moves of your opponent and most of them deal with the self-bias:</p>
<ul>
<li>Too focused on attacking to see that your opponent has the stronger attack and you are better served by defending</li>
<li>Fail to evaluate a tactic to a quiescent position because you feel like you're better than your opponent so it must work out in your favour</li>
<li>You are several points up in material, you don't have to work any more, your opponent should just keel over and give you your well-earned victory, why must they insist on fighting on?</li>
</ul>
<h2>How can I overcome this?</h2>
<p>Short answer: you can't. By definition, it's part of you, unless you are born with some weird genetic mutation. Luckily, there are all sorts of ways to &quot;trick&quot; your brain into avoiding a thought process that is controlled by the self-bias. My favorite trick is simplest of all and it comes from an old adage:</p>
<blockquote>
<p>Before you judge someone walk a mile in their shoes, that way you are a mile away and you have their shoes :)</p>
</blockquote>
<p>To make it clear, what I mean is simply look at the game from your opponen'ts perspective, and search for that &quot;killer&quot; move to win the game, but on his side. That way, you can spot it and direct the game away from it.</p>
 97: <p>If you want to avoid "dumb blunders" - i.e. just dropping a piece you've left hanging on the other side of the board - a simple method is to take an inventory of the position before you do anything else on each move. Checking <strong>which of your pieces are attacked</strong> and <strong>which of your pieces are hanging</strong> would be a good start. The brain will catalogue this information into 8x8-grid punch-card type patterns in your head that act as a warning system against stupid errors.</p>

<p>It can however be surprisingly difficult to take a regimented approach like this even if on the surface it seems quite a trivial task to complete at the start of each of your moves. The brain has a tendency to immediately want to investigate interesting lines and will wander sometimes never to return. Even harder if you're an older player who has never applied such discipline.</p>

<p>But if you stick at it over time it becomes second nature and you just see better and don't blunder as much.</p>
