Learn how to play the opening. Common Opening Themes include:
- Control of the Center
- Development of your pieces to their Best Squares.
- Including ALL your pieces in your Game
- King Safety is most important
The key to opening play is to "Play What You Know and Know What You Play". This means don't play an opening in an important game unless you have studied it and tried it out successfully in off hand games first.
The best way to learn your openings is to keep a note book which contains your tabiya of preferred lines. As you play, you will eventually reach the end of your known analysis. At that point you should research your position and learn the next move(s) so that when the opportunity appears again you will better know what to play. This method will slowly build your opening knowledge and expand your tabiya with useful moves. An automated way of tracking your tabiyas is to use Bookup, also known as Chess Openings Wizard. ChessBase also has some features for saving and analyzing your tabiya.
One mistake that many players make is to try and study too many openings and not learn to play any one of them really well. Using the above method will give you an opening book of lines that you play without wasted effort of learning parts of openings that you never play.
Learn to get the initiative and get a head start on your opponent.