Instructions
Know the difference between strategy and tactics. Tactics are short multi-move combinations that win you material. On the other hand, strategies are the long term plans you have for the entire game.
Read beginner chess books to learn the basic openings, strategies and tactics. Yasser Seirawan's "Winning Chess" series and Jeremy Silman's middlegame books are fantastic resources.
Practice your basic skills against players who are at least as good as you are. If you can, challenge players who are a bit better than you--you won't be completely blown out of the water, and you might learn a few tricks in losing.
Learn about the different opening styles and pick one that suits your game. "Understanding the Chess Openings" by IM Sam Collins is a good place to start.
Get a book of annotated Grandmaster games. Playing through these at your own pace lets you think about them in depth and offers you incredible insight into the workings of top players' minds.
Improve your endgame skills. There are dozens of books covering the details of the endgame, and most of them are as good as the rest. Programs like Chessmaster also make endgame training easy with their automated exercises and drills.