user11676: So, I was a very good player 4 years ago and then due to academic commitments I had to discontinue playing chess. Now, I want to start again but I seem to have lost the old skills and it seems that the quality of my game has dropped very much. I want to again start playing but I don't know where to start from? Is it advisable to start again from scratch as that will take a lot of time? Should I just focus on playing more games? Any pointers or suggestions please?

user10233: 
Play
Tactics
Play out Difficult Positions multiple times from both sides against a decent computer program or a friend with a comparable or higher rating.

You want to simulate and stimulate game play with #3. It is a great training tool to use and is underutilized by just about everyone. Why do you think masters know plans so well in a wide variety of positions? <== SECRET
You play the position multiple times from both sides to investigate different offensive and defensive ideas. <== SECRET

user1716: I had more or less the same situation when university intervened. I have tried a couple of solutions, having returned after five years. I am (almost) back to my old strength now, barely missed an IM norm few months ago. Here is what I can say about the process:

Tactics first: Knowledge and patterns fade slower than your calculation so first things first. Find tactics from actual games which must not be trivial for you, nor too hard. Get out of your comfort zone and get the engine rolling.
Update your opening repertoire: Make it brief, stick with your old openings. I would suggest against starting to play new openings immediately. Find analyzed games (no engine, the more text the better) in your openings and guess the moves.
Play training games: Make sure to go over each and every game in detail afterwards. Postmortem is an invaluable tool. Tournaments is first, otherwise internet and rapid time controls (blitz only before the tournaments to get in shape)
Solve studies: This teaches you endgames and skill of calculation (elimination above all). I believe this helped me most.

Good luck!

user4418: 
Should I just focus on playing more games?

Absolutely!
The single most effective way to improve, regardless of your situation, is to play lots of serious games at standard time rates (so not blitz and rapid). You have been good before. You will be good again, probably even better, if you just start playing serious games (league and congress) more often. 
Playing serious games means that the rules oblige you to write the moves down. A day or two after each game try and make a point of setting up the pieces on a board and going through the game. If you have the time an old tip from the Soviet school of chess is to write annotations for each of your games. This will help you think about where you went wrong and where your opponent went wrong.

user4362: I have always found the fastest way to get rid of some rust to be tactics training. 
I would recommend two steps:
First you do a lot of relatively simple exercises, like game typical 'mate in two' (not chess problems, those can be quite difficult). This will remind your brain to automatically spot the easy stuff and reduce the probability of really bad blunders. You can go through the same positions several times.
Then you do some hard problems with something like 15 minutes per problem, here every problem should be new to you, you should sit down with a clock and write down your solution. This should get you back into tournament shape. 
In my experience this works a lot better than playing blitz online. Playing long games seriously should have a similar effect, but I usually want to get back into shape before I play a really serious game. 

11676: <p>So, I was a very good player 4 years ago and then due to academic commitments I had to discontinue playing chess. Now, I want to start again but I seem to have lost the old skills and it seems that the quality of my game has dropped very much. I want to again start playing but I don't know where to start from? Is it advisable to start again from scratch as that will take a lot of time? Should I just focus on playing more games? Any pointers or suggestions please?</p>
 10233: <ol>
<li>Play</li>
<li>Tactics</li>
<li>Play out Difficult Positions multiple times from both sides against a decent computer program or a friend with a comparable or higher rating.</li>
</ol>

<p>You want to simulate and stimulate game play with #3. It is a great training tool to use and is underutilized by just about everyone. Why do you think masters know plans so well in a wide variety of positions? &lt;== SECRET</p>

<p>You play the position multiple times from both sides to investigate different offensive and defensive ideas. &lt;== SECRET</p>
 1716: <p>I had more or less the same situation when university intervened. I have tried a couple of solutions, having returned after five years. I am (almost) back to my old strength now, barely missed an IM norm few months ago. Here is what I can say about the process:</p>

<ol>
<li>Tactics first: Knowledge and patterns fade slower than your calculation so first things first. Find tactics from actual games which must <strong>not</strong> be trivial for you, nor too hard. Get out of your comfort zone and get the engine rolling.</li>
<li>Update your opening repertoire: Make it brief, stick with your old openings. I would suggest against starting to play new openings immediately. Find analyzed games (no engine, the more text the better) in your openings and guess the moves.</li>
<li>Play training games: Make sure to go over each and every game in detail afterwards. Postmortem is an invaluable tool. Tournaments is first, otherwise internet and rapid time controls (blitz only before the tournaments to get in shape)</li>
<li>Solve studies: This teaches you endgames and skill of calculation (elimination above all). I believe this helped me most.</li>
</ol>

<p>Good luck!</p>
 4418: <blockquote>
  <p>Should I just focus on playing more games?</p>
</blockquote>

<p>Absolutely!</p>

<p>The single most effective way to improve, regardless of your situation, is to play lots of serious games at standard time rates (so not blitz and rapid). You have been good before. You will be good again, probably even better, if you just start playing serious games (league and congress) more often. </p>

<p>Playing serious games means that the rules oblige you to write the moves down. A day or two after each game try and make a point of setting up the pieces on a board and going through the game. If you have the time an old tip from the Soviet school of chess is to write annotations for each of your games. This will help you think about where you went wrong and where your opponent went wrong.</p>
 4362: <p>I have always found the fastest way to get rid of some rust to be tactics training. </p>

<p>I would recommend two steps:</p>

<p>First you do a lot of relatively simple exercises, like <a href="http://wtharvey.com/m8n2.html" rel="nofollow noreferrer">game typical 'mate in two'</a> (not chess problems, those can be quite difficult). This will remind your brain to automatically spot the easy stuff and reduce the probability of really bad blunders. You can go through the same positions several times.</p>

<p>Then you do some hard problems with something like 15 minutes per problem, here every problem should be new to you, you should sit down with a clock and write down your solution. This should get you back into tournament shape. </p>

<p>In my experience this works a lot better than playing blitz online. Playing long games seriously should have a similar effect, but I usually want to get back into shape <em>before</em> I play a really serious game. </p>
