Improving your backswing

From the moment you address the ball all the way through the backswing, there are a number of angles to keep in mind.
 
Start with the stance. Your feet should be spread apart at shoulder-width.

Start with them facing directly ahead of you, then move them outward about 30 degrees.

Next, extend the club to where the ball is resting. The angle of the shaft should be 45 degrees.

Now figure out your target line. That's an imaginary line between the ball and where you want it to go.

The rest of the swing is described for a right-handed golfer. If you're left-handed, reverse everything.

Now swing the club back until your left arm is horizontal. At that point, the end of the grip should be pointed along the target line.

At the top of your backswing, the club should be aligned with your heels, your left arm should be parallel with your shoulders, and your right arm should be cocked at a right angle.

Your shoulders should be turned until they're at a 90 degree angle to the target line.

Now, if the club head is parallel to your shoulders, you're in the right position to start your downswing.

Try taking these steps slowly at first, then practice the motion until you can do it automatically in one smooth motion.