user13565: Sorry if this question is waaay too long, but I just want professional chess players to know exactly what I think and help me. I'd appreciate it if anyone interested went through my question thoroughly to address my problems. Plus, the game's only 20 moves long, so I hope you don't mind having a look at it. 
Here is one of the best (honestly) games I've played. Beating a player rated 300 points above me (before the match, he was 1529, and I was 1229)is unprecedented, for me.
But I've got a few problems. Firstly, I made it to move 10 comfortably only because the Slav defense was one of the few openings I am familiar with, having studied it when I was 13. I don't know why some of the moves in the opening were done, I did them just because they were in the Slav defense.
Next,  I struggled to find the right moves after move 10. Till move 14, I went about with vague plans of building an impregnable defense. You might notice that my pawns sort of inhibited my opponent's minor pieces (that's my take on it, I'm welcome to other opinions).
In the remaining moves, I tried to reposition my pieces because it was the best I felt I could do. My defense might have looked secure to me, but I felt that it was as stable as a deck of playing cards, and moving even a single pawn to mount an attack would likely bring it crashing down (I've learnt this the hard way).
Thing is, my opponent thought a lot on his move and lost on time. I want your advice on a couple of issues:

Was my idea of repositioning my pieces​ from the 10th move onwards good? As in, did I gain anything by doing so? I didn't have any other ideas.
How would you rate my defense? Were my ideas good? I was just implementing Fred Reinfeld's advice. 
What should I do in such situations(which I often come across in middle games), where no attack seems to present itself to me? I'm usually good at noticing forks, checks, captures and so on(forcing moves), but when there are none, I sort of run out of ideas. I often risk pushing a pawn to mount an attack, only to see my defense unravel!
Plus, I can't predict my opponent's thoughts. What general rules must I follow, especially if my opponent's moves mystify me(as they seem to have no direct purpose).
If my moves weren't good (quite possible), please suggest an alternative game plan. Mine was to defend solidly and pounce on weaknesses. But defending is okay in the beginning, I have no idea how to carry on my plans in the middle game. I often resort to weak moves when I see no strong ones, just to keep moving. To repeat something that is obvious, I find it hard to mount attacks due to my defensive choices. But then, what else can I do? And don't some famous players play defensively?
To summarize, I want to know if my moves (10th onwards)were effective, and if they weren't, what I should have done. 

I value both general and specific advice equally!
I played black.
 [Site "Chess.com"]
 [Date "Jun 20, 2017"]
 [White "RDR22"]
 [Black "JoshuaFischer007"]
 [Result "0-1"]
 [WhiteElo "1508"]
 [BlackElo "1337"]
 [TimeControl "1 in 0 day"]
 [Termination "JoshuaFischer007 won on time"]
 [FEN ""]

 1. d4 d5 2. c4 c6 3. Nc3 Nf6 4. Nf3 e6 5. Bg5 h6 6. Bh4 Be7 7. e3 O-O 8. cxd5 exd5 9. Be2 Bf5 10. O-O Nbd7 11. a3 a6 12. b4 Qc7 13. Bd3 Bxd3 14. Qxd3 Rae8 15. Rac1 Bd6 16. Bxf6 Nxf6 17. g3 Re7 18. Rc2 Rfe8 19. Rfc1 Qd7 20. Kg2 g6  0-1

PS: Did I get the tags right?

user4543: You played fine, denying him play but he really lost on time before the game started.

user11629: 
I made it to move 10 comfortably only because the Slav defense was one of the few openings I am familiar with, having studied it when I was 13. I don't know why some of the moves in the opening were done, I did them just because they were in the Slav defense.

At your level you should really forget about any "official" openings and focus on learning general principals, common themes like pawn breaks, weak/strong pieces,... and how to evaluate a position. Based on this you will come up with a plan that either improves on your weaknesses or works against your opponent's weaknesses. This will be useful for opening/middlegame/endgame. There is really no point following blindly some moves because they are in the book without understanding the idea behind them.
Regarding your game:
White played the opening rather timidly, posing no problems to you. 8. cxd5 exd5 helped black to free the bad bishop on c8. 9. Bd3 might have been more ambitious, aiming for the black king. 9. Be2 on the other hand gave you a nice square on f5 for your bishop.
I am not a Slav player but based on the position around move 10, I believe the natural plan for white is to play against the pawn on c6 by putting rook(s) on the c file and pushing the pawn to b5 (likely needs support from a pawn on a4). Black could work against this plan by

starting a counterattack on the kingside, making use of his more active pieces there or
by defending passively against the b5 break playing a6, perhaps the queen to d7, transferring a knight to d6, etc. Or prevent white from playing a4 by attacking the b4 pawn. Also, by just playing a6 you always get the option to take on b5 once (axb5) and get the open a file for counterplay. In that case you want your rook to be on a8.

White did not do much after move 10, exchanged a few pieces and played g3 which weakens the light squares (playing h3 would be better if you want to free the Nf3 from protecting the h2 pawn).
You doubled rooks on the e file, however you are not going to achieve anything there with just the rooks. You really need to play f5 and f4 (if necessary after g5) to weaken the white pawn structure. For this plan, it is not clear whether you want to have both rooks on the e file or perhaps one on the e and one on the f file.
Starting with 15. Rac1, you are in danger of running into tactics related to Nxd5 or Nxb5 (after b5 axb5)  because of the pin of the c6 pawn. Might want to move your queen out of this pin, e.g. to d7 or b8.
It is unclear to me why you played 20...g6.

To your specific questions:

Was my idea of repositioning my pieces​ from the 10th move onwards good? As in, did I gain anything by doing so? I didn't have any other ideas.

Looks mostly like natural development to me. One could argue about the rook placement and the queen as per above.

How would you rate my defense? Were my ideas good?

You did not say what your "ideas" actually were. The moves were natural and mostly fine, but it was not really a challenging game/opening. Please replace the word "defense" with "opening play" in the question, as otherwise it suggests that you had to defend which you did not.

What should I do in such situations(which I often come across in middle games), where no attack seems to present itself to me?

That is the tricky part of chess. In a position like this, where neither side has any real weaknesses and not much tactics going on, you can try to create weaknesses. This is often done by pawn breaks. For instance in the position you have, white wants to play b5 in order to either (i) capture on c6 (or on a6) which would leave you with a backward pawn on c6 which could easily be attacked; or (ii) if you capture twice on b5, leave you with doubled isolated pawns on the b file which would also be an easy target for the white rooks.
In a similar fashion, black could try to work against the e3 pawn or against the white king by breaking open the white pawn structure with f4.

Plus, I can't predict my opponent's thoughts. What general rules must I follow, especially if my opponent's moves mystify me(as they seem to have no direct purpose).

Basically in the same way that you are coming up with a plan for yourself, you should come up with a plan for your opponent... and then see if that plan poses any danger to you, etc If you can't figure out what purpose your opponent's move have (as in this case they indeed seem to have no purpose), there is nothing you can do but go through with your plan.

If my moves weren't good (quite possible), please suggest an alternative game plan. 

They were pretty decent moves for a player of your level. Alternative I suggested above.

Mine was to defend solidly and pounce on weaknesses. 

Solid it was, not sure where you pounced on weaknesses.

But defending is okay in the beginning, I have no idea how to carry on my plans in the middle game. I often resort to weak moves when I see no strong ones, just to keep moving. 

As above, you are not defending here. The word "defense" in "Slav defense" (or any other chess opening name) has no meaning really. It is not good to play without plan.
It is essential to understand and evaluate a chess position in order to come up with a plan. Focus on learning about pawn structures (see link for themes/plans), about weak/strong pieces, about pawn breaks, about backward/isolated/doubled pawns, about safe/unsafe king positions (potential for attack), etc
Reading or watching annotated/commented games is a good idea as is having a better player go through your own games.

To repeat something that is obvious, I find it hard to mount attacks due to my defensive choices. But then, what else can I do? And don't some famous players play defensively?

Yes, some players play more defensively than others, but still you are not going to win a game (most of the time) by just moving aimlessly around. Even defensive players, will need to find ways for counter play as otherwise they would just be overrun.

13565: <p>Sorry if this question is waaay too long, but I just want professional chess players to know exactly what I think and help me. I'd appreciate it if anyone interested went through my question thoroughly to address my problems. Plus, the game's <strong>only 20 moves long</strong>, so I hope you don't mind having a look at it. </p>

<p>Here is one of the best (honestly) games I've played. Beating a player rated 300 points above me (before the match, he was 1529, and I was 1229)is unprecedented, for me.
But I've got a few problems. Firstly, I made it to move 10 comfortably only because the Slav defense was one of the <strong>few</strong> openings I am familiar with, having studied it when I was 13. I don't know why some of the moves in the opening were done, I did them just because they were in the Slav defense.</p>

<p>Next,  I struggled to find the right moves after move 10. Till move 14, I went about with vague plans of building an impregnable defense. You might notice that my pawns sort of inhibited my opponent's minor pieces <em>(that's my take on it, I'm welcome to other opinions).</em>
In the remaining moves, I tried to reposition my pieces because it was the best I felt I could do. My defense might have looked secure to me, but I felt that it was as <em>stable as a deck of playing cards</em>, and moving <em>even a single pawn to mount an attack</em> would likely bring it <strong>crashing down</strong> (I've learnt this the hard way).
Thing is, my opponent thought a lot on his move and lost on time. I want your advice on a couple of issues:</p>

<ul>
<li><p>Was my idea of <em>repositioning</em> my pieces​ from the 10th move onwards good? As in, did I gain anything by doing so? I didn't have any other ideas.</p></li>
<li><p>How would you rate my defense? Were my ideas good? I was just implementing Fred Reinfeld's advice. </p></li>
<li><p>What should I do in such situations(which I often come across in middle games), where no attack seems to present itself to me? I'm usually good at noticing forks, checks, captures and so on(forcing moves), but when there are none, I sort of run out of ideas. I often risk pushing a pawn to mount an attack, only to see my defense unravel!</p></li>
<li><p>Plus, I can't predict my opponent's thoughts. What general rules must I follow, especially if my opponent's moves mystify me(as they seem to have no direct purpose).</p></li>
<li><p>If my moves weren't good (quite possible), please suggest an <em>alternative game plan</em>. Mine was to <em>defend solidly and pounce on weaknesses</em>. But defending is okay in the beginning, I have no idea how to carry on my plans in the middle game. I often resort to weak moves when I see no strong ones, just to keep moving. <strong>To repeat something that is obvious</strong>, I find it hard to mount attacks due to my defensive choices. But then, what else can I do? And don't some famous players play defensively?</p></li>
<li><p>To summarize, I want to know if my moves (10th onwards)were effective, and if they weren't, what I should have done. </p></li>
</ul>

<p>I value <em>both general and specific advice</em> equally!</p>

<p>I played <strong>black.</strong></p>

<pre><code> [Site "Chess.com"]
 [Date "Jun 20, 2017"]
 [White "RDR22"]
 [Black "JoshuaFischer007"]
 [Result "0-1"]
 [WhiteElo "1508"]
 [BlackElo "1337"]
 [TimeControl "1 in 0 day"]
 [Termination "JoshuaFischer007 won on time"]
 [FEN ""]

 1. d4 d5 2. c4 c6 3. Nc3 Nf6 4. Nf3 e6 5. Bg5 h6 6. Bh4 Be7 7. e3 O-O 8. cxd5 exd5 9. Be2 Bf5 10. O-O Nbd7 11. a3 a6 12. b4 Qc7 13. Bd3 Bxd3 14. Qxd3 Rae8 15. Rac1 Bd6 16. Bxf6 Nxf6 17. g3 Re7 18. Rc2 Rfe8 19. Rfc1 Qd7 20. Kg2 g6  0-1
</code></pre>

<p>PS: Did I get the tags right?</p>
 4543: <p>You played fine, denying him play but he really lost on time before the game started.</p>
 11629: <blockquote>
  <p>I made it to move 10 comfortably only because the Slav defense was one of the few openings I am familiar with, having studied it when I was 13. I don't know why some of the moves in the opening were done, I did them just because they were in the Slav defense.</p>
</blockquote>

<p>At your level you should really forget about any "official" openings and focus on learning general principals, common themes like pawn breaks, weak/strong pieces,... and how to evaluate a position. Based on this you will come up with a plan that either improves on your weaknesses or works against your opponent's weaknesses. This will be useful for opening/middlegame/endgame. There is really no point following blindly some moves because they are in the book without understanding the idea behind them.</p>

<p>Regarding your game:</p>

<p>White played the opening rather timidly, posing no problems to you. 8. cxd5 exd5 helped black to free the bad bishop on c8. 9. Bd3 might have been more ambitious, aiming for the black king. 9. Be2 on the other hand gave you a nice square on f5 for your bishop.</p>

<p>I am not a Slav player but based on the position around move 10, I believe the natural plan for white is to play against the pawn on c6 by putting rook(s) on the c file and pushing the pawn to b5 (likely needs support from a pawn on a4). Black could work against this plan by</p>

<ol>
<li>starting a counterattack on the kingside, making use of his more active pieces there or</li>
<li>by defending passively against the b5 break playing a6, perhaps the queen to d7, transferring a knight to d6, etc. Or prevent white from playing a4 by attacking the b4 pawn. Also, by just playing a6 you always get the option to take on b5 once (axb5) and get the open a file for counterplay. In that case you want your rook to be on a8.</li>
</ol>

<p>White did not do much after move 10, exchanged a few pieces and played g3 which weakens the light squares (playing h3 would be better if you want to free the Nf3 from protecting the h2 pawn).</p>

<p>You doubled rooks on the e file, however you are not going to achieve anything there with just the rooks. You really need to play f5 and f4 (if necessary after g5) to weaken the white pawn structure. For this plan, it is not clear whether you want to have both rooks on the e file or perhaps one on the e and one on the f file.</p>

<p>Starting with 15. Rac1, you are in danger of running into tactics related to Nxd5 or Nxb5 (after b5 axb5)  because of the pin of the c6 pawn. Might want to move your queen out of this pin, e.g. to d7 or b8.</p>

<p>It is unclear to me why you played 20...g6.</p>

<hr>

<p>To your specific questions:</p>

<blockquote>
  <p>Was my idea of repositioning my pieces​ from the 10th move onwards good? As in, did I gain anything by doing so? I didn't have any other ideas.</p>
</blockquote>

<p>Looks mostly like natural development to me. One could argue about the rook placement and the queen as per above.</p>

<blockquote>
  <p>How would you rate my defense? Were my ideas good?</p>
</blockquote>

<p>You did not say what your "ideas" actually were. The moves were natural and mostly fine, but it was not really a challenging game/opening. Please replace the word "defense" with "opening play" in the question, as otherwise it suggests that you had to defend which you did not.</p>

<blockquote>
  <p>What should I do in such situations(which I often come across in middle games), where no attack seems to present itself to me?</p>
</blockquote>

<p>That is the tricky part of chess. In a position like this, where neither side has any real weaknesses and not much tactics going on, you can try to create weaknesses. This is often done by pawn breaks. For instance in the position you have, white wants to play b5 in order to either (i) capture on c6 (or on a6) which would leave you with a <a href="https://en.wikipedia.org/wiki/Backward_pawn" rel="nofollow noreferrer">backward pawn</a> on c6 which could easily be attacked; or (ii) if you capture twice on b5, leave you with doubled isolated pawns on the b file which would also be an easy target for the white rooks.</p>

<p>In a similar fashion, black could try to work against the e3 pawn or against the white king by breaking open the white pawn structure with f4.</p>

<blockquote>
  <p>Plus, I can't predict my opponent's thoughts. What general rules must I follow, especially if my opponent's moves mystify me(as they seem to have no direct purpose).</p>
</blockquote>

<p>Basically in the same way that you are coming up with a plan for yourself, you should come up with a plan for your opponent... and then see if that plan poses any danger to you, etc If you can't figure out what purpose your opponent's move have (as in this case they indeed seem to have no purpose), there is nothing you can do but go through with your plan.</p>

<blockquote>
  <p>If my moves weren't good (quite possible), please suggest an alternative game plan. </p>
</blockquote>

<p>They were pretty decent moves for a player of your level. Alternative I suggested above.</p>

<blockquote>
  <p>Mine was to defend solidly and pounce on weaknesses. </p>
</blockquote>

<p>Solid it was, not sure where you pounced on weaknesses.</p>

<blockquote>
  <p>But defending is okay in the beginning, I have no idea how to carry on my plans in the middle game. I often resort to weak moves when I see no strong ones, just to keep moving. </p>
</blockquote>

<p>As above, you are not defending here. The word "defense" in "Slav defense" (or any other chess opening name) has no meaning really. It is not good to play without plan.</p>

<p>It is essential to understand and evaluate a chess position in order to come up with a plan. Focus on learning about <a href="https://en.wikipedia.org/wiki/Pawn_structure" rel="nofollow noreferrer">pawn structures</a> (see link for themes/plans), about weak/strong pieces, about pawn breaks, about backward/isolated/doubled pawns, about safe/unsafe king positions (potential for attack), etc</p>

<p>Reading or watching annotated/commented games is a good idea as is having a better player go through your own games.</p>

<blockquote>
  <p>To repeat something that is obvious, I find it hard to mount attacks due to my defensive choices. But then, what else can I do? And don't some famous players play defensively?</p>
</blockquote>

<p>Yes, some players play more defensively than others, but still you are not going to win a game (most of the time) by just moving aimlessly around. Even defensive players, will need to find ways for counter play as otherwise they would just be overrun.</p>
