user23189: I was wondering what skills, abilities, and knowledge is needed to reach consistent 2300 FIDE elo and therefore become a FIDE Master. Now, I'm not asking about the innate abilities, but those which you can acquire by practice and study:
A pretty simple list:  

Have a decent knowledge on most/or all of the typical openings, and be very good at one (or more) for each side.  
Have a deep positional/technical game, having memorize and understand grand masters games, so you develop an intuition of the position.  
Knowledge of the endgames. Pretty important. How the positions are going to be simplify and the chances in both sides.  
Tactics.


user4418: There are 3 key things you need to do.

First and most important you must love chess so much that you feel you must play chess every day.
Play a lot of serious (preferably competition) over-the-board chess at a slow (standard, not rapid or blitz) time control.
Analyse your games in depth without an engine. If you use an engine you are cheating yourself just as much as using an engine in a real game cheats your opponent. Ideally you would have a study partner with whom you could go over your analysis, explaining what you found in your moves and your opponent's moves.


user11749: Let me build on @Brian Towers' answer: Love, Play and Analyze! But let me add some points.

Love Chess. because you'll need it to train a lot and go through your list.


GM Shipov suggests that the main requirement for success at chess is to be 100% dedicated and interested in the game. If you just a little interested, you will not be able to make serious progress. 


Play Chess. Competition is indeed crucial. Play competitively over-the-board and online. Blitz and rapid games may help you practice and test openings. But it is true that classic games (90 min/40 moves + 30 min and increment) are the most important, as you will devote on average about four hours playing chess and thinking. In his book Deep Thinking, Gary Kasparov writes that a player is so concentrated during a game that the quality of her/his analysis is even better than in post-mortem. An addition: choose your tournaments to face stronger opponents. You will learn from them.


GM Kazhgaleyev writes that in order to improve at chess you need to play
  more tournament games, study classics, solve tactics and endgame
  studies as well as be passionate about chess in general. That's how
  you can get to that 2200-2300 Elo.


Analyze Chess. But the most important thing is to analyze the losses because they will give you the feedback you need to improve. We loose because we make mistakes, at least the last one! After each game, write down your ideas and your analysis, the ones you had during the game. Then you can use a computer to check your analysis. The computer or a coach will help you identify your mistakes. You will improve by not repeating them.


GM Shipov believes in importance of deep analysis of your own games
  and ability to judge yourself fairly. If you lose a game, don’t think
  that it’s because of that silly move you played, find the real cause
  and improve!

Quotes are from How to Reach 2200 ELO – According to GM Tkachiev... not too far from the FIDE Master level... 

23189: <p>I was wondering what skills, abilities, and knowledge is needed to reach consistent 2300 FIDE elo and therefore become a FIDE Master. Now, I'm not asking about the innate abilities, but those which you can acquire by practice and study:</p>

<p>A pretty simple list:  </p>

<ul>
<li>Have a decent knowledge on most/or all of the typical openings, and be very good at one (or more) for each side.  </li>
<li>Have a deep positional/technical game, having memorize and understand grand masters games, so you develop an intuition of the position.  </li>
<li>Knowledge of the endgames. Pretty important. How the positions are going to be simplify and the chances in both sides.  </li>
<li>Tactics.</li>
</ul>
 4418: <p>There are 3 key things you need to do.</p>

<ol>
<li>First and most important you must love chess so much that you feel you must play chess every day.</li>
<li>Play a lot of serious (preferably competition) over-the-board chess at a slow (standard, not rapid or blitz) time control.</li>
<li>Analyse your games in depth without an engine. If you use an engine you are cheating yourself just as much as using an engine in a real game cheats your opponent. Ideally you would have a study partner with whom you could go over your analysis, explaining what you found in your moves and your opponent's moves.</li>
</ol>
 11749: <p>Let me build on @Brian Towers' answer: Love, Play and Analyze! But let me add some points.</p>

<ol>
<li><strong>Love Chess.</strong> because you'll need it to <strong>train</strong> a lot and go through your list.</li>
</ol>

<blockquote>
  <p><a href="https://en.wikipedia.org/wiki/Sergei_Shipov" rel="noreferrer">GM Shipov</a> suggests that the main requirement for success at chess is to be 100% dedicated and interested in the game. If you just a little interested, you will not be able to make serious progress. </p>
</blockquote>

<ol start="2">
<li><strong>Play Chess.</strong> Competition is indeed crucial. <strong>Play competitively</strong> over-the-board and online. Blitz and rapid games may help you practice and test openings. But it is true that classic games (90 min/40 moves + 30 min and increment) are the most important, as you will devote on average about four hours playing chess and thinking. In his book <a href="https://www.goodreads.com/book/show/31934455-deep-thinking" rel="noreferrer">Deep Thinking</a>, Gary Kasparov writes that a player is so concentrated during a game that the quality of her/his analysis is even better than in post-mortem. An addition: choose your tournaments to face <strong>stronger opponents</strong>. You will learn from them.</li>
</ol>

<blockquote>
  <p><a href="https://en.wikipedia.org/wiki/Murtas_Kazhgaleyev" rel="noreferrer">GM Kazhgaleyev</a> writes that in order to improve at chess you need to play
  more tournament games, study classics, solve tactics and endgame
  studies as well as be passionate about chess in general. That's how
  you can get to that 2200-2300 Elo.</p>
</blockquote>

<ol start="3">
<li><strong>Analyze Chess.</strong> But the most important thing is to <strong>analyze the losses</strong> because they will give you the feedback you need to improve. We loose because we make mistakes, at least the last one! After each game, write down your ideas and your analysis, the ones you had during the game. Then you can use a computer to check your analysis. The computer or a coach will help you identify your mistakes. You will improve by not repeating them.</li>
</ol>

<blockquote>
  <p><a href="https://en.wikipedia.org/wiki/Sergei_Shipov" rel="noreferrer">GM Shipov</a> believes in importance of deep analysis of your own games
  and ability to judge yourself fairly. If you lose a game, don’t think
  that it’s because of that silly move you played, find the real cause
  and improve!</p>
</blockquote>

<p>Quotes are from <a href="https://thechessworld.com/articles/training-techniques/how-to-reach-2200-elo-according-to-gm-tkachiev/" rel="noreferrer">How to Reach 2200 ELO – According to GM Tkachiev</a>... not too far from the FIDE Master level... </p>
