If you are having problems with misdirected shots the first thing to look at is your ball position. Your ball position has a lot to with the initial direction of departure of your ball. For a quick tutorial on what controls ball flight and direction go to Ball flight explained.
Generally the further forward in your stance the ball is, the more likely you are to hit it left and the further back it is, the more likely you are to hit it right. Ideally you want your club to make contact with the ball at a point directly in front of you and at the point where the club head is as far away from you as it ever gets.
There are other reasons to vary your ball position. If you need to hit down on the ball with a descending shot, move the ball slightly back in your stance.
If you are playing a driver move the ball slightly forward in your stance to take advantage of the fact the club head is starting to ascend there and gain some height in your ball flight.
Ensure that that your swing plane and path are relatively constant before experimenting with ball position. Concentrate on an “in to out” swing path rather than its opposite.
Once you have a fairly consistent and reliable swing, experiment with ball position and you will make progress. Remember when you adjust ball position move it very little, a couple of inches is a big adjustment.