Allen Doyle is a player on the Champions Tour and has one of the shortest swings in the world, but he still manages to occasionally hit the ball more than 300 yards. Growing up in New England, Doyle was relegated to the basement with a low ceiling where he perfected his swing during the winter. If you can develop a short swing, you will have less trouble keeping it in tempo and you will hit fewer errant shots.
Address the ball with your feet a bit further apart. This will help you reduce your hip turn on the backswing and help shorten it.
On your backswing, keep the foot nearest the target on the ground.
Stay in balance throughout your swing. People with a long swing tend to sway away from the target on their backswing to achieve a full turn and a long swing. If you stay centered throughout the swing, you will be limited physically to how much you can turn your body, thus reducing the length of your swing.
Avoid the so-called "flying elbow." Instead, try tucking your elbow into your side on your backswing. If you do, your hands will not be as high at the top of your swing and you will effectively shorten it.
Slow down. Most people who overswing tend to speed up their swing. A good way to approach this is to stop briefly at the top before beginning your downswing.
Begin moving your hips forward before you complete your backswing. Pay no attention to balls you might hit by doing this as they probably will go to the right if you are right-handed. Instead, it will create the image of shortening your backswing.
Make sure your shoulders and hips move at the same time you are taking the club back. Too often, amateurs will restrict their shoulder turns, hit the ball a shorter distance, then try to make up for it by lengthening their swings. Remember that it comes down to how fast the club head is traveling when it makes contact with the ball that will translate to distance. If your golf swing is in sync, you can hit the ball a long way, even with a half-swing.
Tips & Warnings
You have the choice: Hit the ball about 300 yards into the trees or 230 yards into the middle of the fairway. With a shorter golf swing, you will be in more control and will hit fewer errant shots.