The swing plane of your golf swing is easily one of the most important components of the shot. It plays a major role in determining contact, accuracy, spin, and everything else that results from these things. So many golfing flaws can be fixed by improving your swing plane, resulting in lower scores and better rounds of golf. Here is some information on the swing plane and ways to improve your own.
The swing plane is the optimal area through which you want to swing your club. It is defined by the angle the club makes when you are set up to take the shot. The key is to always move the club at this angle at every point during your swing. Suppose, for example, that the club makes a 60 degree angle with the ground as you are set, ready to hit. As you move into your backswing, you should pull the club back so that it always maintains this angle. Even at the top of your backswing and as you begin to swing towards the ball, you should continue along this 60 degree angle. This is crucial because it ensures that you come down and strike the ball precisely as you were set up. Drifting from this optimal angle is often the cause of slicing and hooking the ball as you strike the ball with a different club face than as you were originally set.
There are a number of ways to fix your swing plane. I would suggest videoing yourself swinging normally and then watching to see how you deviate from the correct plane. It's an easy way to quickly see where flaws are and how to best fix them. Practice swinging slowly with a mirror to see what the correct plane feels like. Try to get the form down before swinging too hard. Once you think you are comfortable with the right plane, swing harder and eventually start hitting some balls.