Three things I forgot to cover are:
If you are a beginning player, try to play 1.e4 and open, messy, tactical positions.
The second thing is, for more complicated problems, a good book is Chess Informant's Chess Combinations book (I can't remember the exact title). The CT-ART 4.0 program is also excellent.
The third thing, use blitz as a tool to improve your chess. This is best done by analyzing every game after you play it. The benefit of playing blitz is that you see so many more positions in a short amount of time compared to playing a long game. It improves your chess intuition. Blitz also makes you calculate quicker. Whenever you make a move, try to think about 3 moves ahead. Don't worry so much about your rating. The key thing is to use your time efficiently.
One general suggestion is that you should try ot recreate otb conditions when you are training. If you assume a lax attitude towards your training, then you will be unprepared otb. Great players always keep sharp by solving chess studies. Time yourself. Monitor yourself. The great thing about chess is that it is a self-guided activity, unless you are lucky enough to get a coach of course. If you don't have a coach, don't despair. There are many self-taught grandmasters.The new generation has been brought up on computers and all the resources are right there at your fingertips.
Hmm, so, don't mind the title of this post. It was a bit presumptuous of me to write that and the content of the original post was perhaps a bit off the mark. Here is another version, perhaps more suitable in this forum, considering the comments I've recieved. Anyways, let's get to it...
The first step is to attain tactical mastery. This is done by solving chess problems. The best way to make sure that you don't leave out this key aspect of training, because of laziness, procrastination, or whatever reason, is to set a daily quota for yourself. I would recommend an hour a day until a certain 'otb' rating is achieved. After you get to about a 2000 otb rating, it is not so much about drilling out tactics as it is about understanding how and why they work along with how to go about finding them in a real game. The best way to do this is to understand the tactical motifs. After every problem you solve, ask yourself what happened. Did you use a Pin? Skewer? Fork? Was it Interference? Deflection? Double Attack? Piece Overload? There are so many of these and any player would do well to understand how they work. From personal experience, I will recommend using chesstempo.com for regular training and the chess.com tactics trainer a few days before a tournament. The added element of time pressure really makes you sharp for a tournament.
One aspect of training that many players miss out on is board visualization. Idiots like me think that when it comes to chess, tactics are like money in the bank, the more the better. However, apart from tactical vision, every player needs the ability to see forward a few moves. After all, chess is about analysis. Analysis is basically evaluating arising positions. So when you sit down at a board and play a serious game, you want to be able to calculate and then evaluate the position you arive at. This is only possible if you can see the board in your head to some extent. There are several methods to train visualization. Solving more complex problems will require you to deal with longer variations. Playing chess with the blindfold option on chess.com is another way. There are some websites that ask you about the colours of the squares and other interesting drills which help to hone your board vision. From personal experience, I don't recommend training this aspect till you are around 2000. People will disagree but I am currently around 1800 CFC and my board vision is probably the worst ever. I am sure most people would be happy with around a 2000-2200 rating so this aspect is not as important as the other perhaps. Use your own judgement here anyways.
Endgames are a touchy topic. Let's put it this way: If you are an aspiring junior with a great future in chess ahead of you, do not neglect endgames. The Russian School of Chess has worked wonders and aspiring grandmasters would do well to follow the great example. For the rest of you who would be happy with a low level master title like NM, I would recommend mastering only the basics. Dvoretsky's Endgame Manual is definitely recommended. Jeremy Silman's endgame book is also a very good one as categorizes endgames according to rating levels. Shereshevsky's Endgame Strategy is also another amazing book which will open your eyes to non-conventional endgame approaches. It delves into less concrete but far more amazing ideas like the idea of two weaknesses, patience, etc. I think Dvoretsky's Endgame Manual alone can probably get you to NM, however. Once again, it is up to you.
Opening Preparation is another contentious topic. My recommendation might anger some people. I think that people should stay away from openings with a lot of theory if they are only aiming for, say, a 2000-2200 rating. Learning an opening like the Najdorf comes with a huge burden. Then again, if you are young and you are trying to become a grandmaster, then by all means, go for it. The audience I am speaking to here is different, however. I know players who play nothing but 1.g3 and 1...g6 and they become masters. I know one NM, soon to be FM who plays nothing but 1.g3 and 1...b6. I would recommend picking something solid though, for black at least. An opening like the Slav, French, Sicilian w/ e6, will give you a lot of confidence when you step into your games. For a long time I played 1...g3 and 1...g6 and I found that I was going into games with a rather depressed mentality since I knew I would be cramped and half-dying by the third move. That is not to say that I didn't get excellent results with the openings. It is very easy to prepare unorthodox openings and map out all the transpositions, but there comes a time when you just think, to hell with it. Anyways I am rambling too much. On to the next point...
Here is a good way to prepare your opening repertoire:
First you get your hands on a chess database software and a bunch of games. Chessbase is the best. Then you go to chessok.com or the TWIC site and download all the latest games every week and append them to your database. That will ensure that you stay current and are aware of the latest trends in opening theory. Then you create two databases, one for white and one for black. On chessbase you can make them repertoire databases if you right click on them and click properties. That makes it easy to add variations. Create an outline for the repertoire and for every major variation, save a seperate game to your database. Then you filter the database and find about 50 games played between grandmasters rated over 2600 in each of the variations. That will give you about 1500 games at the end of it all which will cover all your openings. Go through these games and mark them up. Analyze them by yourself. Don't worry if you do a bad job. Going through all those games will improve your understanding and intuition. You will see a lot of the same manoeuvres. Also, you will see how moves developed over time. Of course, there won't be just 50 games in the database so you will have to filter them by changing the rating levels and dates till you get to 50 for each variation. The next step is to come up with the actual moves for your repertoire. That is done by using your newly acquired understanding and a chess engine like Houdini, which can be obtained online for free, to sift through moves and pick out the best and most recently played ones. Make sure you know why you are choosing those moves and why they are the best.
So far what I have mentioned might seem like a ton of work. It is, but it can be broken down into manageable portions. I suggest doing 1 hour of tactics everyday along with 1 hour of game analysis till you get through the 1500, or so, games. 5 games everyday is quite manageable. In a year you can be finished, just try dividing 1500 by 5... It really is doable.
So far, with this plan, I really think anybody can become a master in two years. Here is some further information though...
Youtube is your friend. There are so many free chess lectures on youtube.
http://www.youtube.com/user/STLChessClub
http://www.youtube.com/user/ChessFriendsDotCom?feature=watch
http://www.youtube.com/user/Barkyducky
These are just a few, but there are lots more.
If you are a complete beginner, I suggest using the resources on chess.com or chessclub.com till you are good enough to take up the plan delineated above.
One more thing which I have no idea about, is establishing a thought process. This is one aspect of chess which I have yet to find out more about. I expect I will have to read Kotov's books for it. What I can recommend though, is to try and make your thinking efficient. When you begin calculating a variation, try to finish it before moving on. I suggest playing solitaire chess to train this. Take your favourite grandmaster, or one that plays your openings, and try to guess his or her moves. Take your time and really try to get inside their head. I managed to learn a lot about positional play by trying to emulate Ulf Andersson and guess his moves for example.
I've probably missed lots but this is it for now. Good luck!