You're in an interesting position -- most players, especially below master level, are much better at attack than at defense. In fact, adopting an "attacking" style that is not necessarily perfectly sound (i.e., gambits that trade material for initiative) will very often result in the opponent "folding" under the pressure of a steady onslaught.
+1 to Shannon for recommending endgame study. It's my favorite part of the game, personally. When you know endgames well, you will see in your games the opportunity to steer the game (by making certain trades of material and creating certain pawn structures, for example) toward favorable endgames and away from unfavorable ones.
Of course, study of tactics is really important, especially in developing attacks. You say you love to control the center -- well there's a reason for doing this in chess, it's to give your pieces a launching point to attack! If you can amass your army in the center against a point around the opponent's king, beyond your opponent's ability to defend, you can win by throwing material at the opponent's king to open lines to the king, then mount a checkmating attack (as Fischer said, "sac, sac, mate!").
One thing famous chess instructor National Master Dan Heisman (http://danheisman.com) recommends is to study annotated collections of master games, relatively quickly. After going through a sufficient number of games (around a thousand or so? That's why you should go through them quickly!), you'll really start to get a feel for moves that masters make, and how they take advantage of positional advantages like center control.
Also +1 to BlueRaja for Art of Attack in Chess. A great book about attacking themes and patterns, so you can recognize the possibilities for attacking the king in your own games as well.