1) Study the games of masters. I would recommend earlier masters like Morphy, Lasker, Capablanca, etc. Studying their "simple" games will better your understanding to study more "complicated" games of Fischer, Karpov, Kasparov, Anand or Carlsen.
2) Study the endgame. I recommend Understanding Chess Endgames by John Nunn.
3) Practice and improve your tactical skills. There are many online tactics websites that can help you in that regard, like chesstempo.
4) Enjoy playing chess! Without enjoyment, it's difficult to learn. But don't waste time playing useless 2 or 3 minute blitz games. These won't help you to improve much. Play games with longer time controls, especially in tournaments if possible.
5) Get a good chess engine to analyze your games. I would recommend Stockfish, which is a free engine. However, if you're willing to spend more money, I recommend a powerful engine like Houdini with Chessbase 12. Note that you can also use Stockfish with ChessBase 12. I often use it myself. It's a very strong engine and Houdini is just very sligtly better (for beginners, that shouldn't make much of a difference).
6) Never leave any of your games unanalyzed. That's a serious waste of the time you have spent playing those games and also a loss of the things you could potentially have learned. Never put off analyzing a game for more than a week. My experience is that you remember the lessons learned from your games the earlier you analyze your games. Of course, you need to make good notes on your games.
7) Watch this inspiring video! :) Bobby Fischer - Anything to Win. Caution: I'm asking you to be inspired only by the way Bobby Fischer trained to play chess and win; not to be inspired by his paranoia or his other questionable activities!
8) Study the openings and opening principles. Although this isn't that important for beginners compared to the other things I mentioned, it is nevertheless very important to play good openings to have good positions to play.