As I developed my game as a young golfer I was always looking for more power. I was looking for more power and I found it because I learned to build a solid wall of my left side, a wall that would not move under any circumstances.
The theory is, if I have a strong left side and can hit against it, then I can develop a lot of power. I need all the power I can find.
This straight left wall begins at the top of the left shoulder and continues to the left foot. When I say straight, I mean it literally. The worry is not about my head or my hands, but about the body. It should be perfectly vertical.
I used to do special isometric exercises to help build this left side. I would go home and stand with my left shoulder, hip, leg, and foot directly against a door frame. Then I would exert isometric pressure to build the muscles on my left side.
Another exercise consisted of placing an imaginary club in my right hand. I would take an imaginary backswing, then the downswing. And always during these swings I concentrated on keeping the entire left side of my body perfectly straight. I also made sure all points of that side touched and never left the door frame. The idea was to practice so much that keeping that solid left wall became almost as natural as inserting the car key into the ignition.
There is only one way to develop this wall, and that is through constant practice and exercise. As you will learn, everything evolves from being perfectly straight on all your shots that require power.
As you are practicing, you will begin to notice that you are starting to dig your right foot into the surface of the turf. You dig in with the inside of the sole of your right shoe. This is very important because digging your right foot gives you the thrust and power you need for distance hitting.
The positioning of the left foot is extremely important, too. At the conclusion of the swing, in the case of the smaller golfer, the left foot should be pointing to your right. In other words, it must be slightly pigeon-toed. If you move your left foot, the whole left side of the wall moves out of position and you make a poor shot.
I cannot stress this point too much, for smaller golfers. During the downswing the left foot serves as a brace. If the brace breaks, so does the swing. For the normal-sized golfer, I recommend that the left foot remain straight or very slightly turned to the left.
There is no one thing that gives me power. It is a combination of many difficult moves, and these moves must all become secondary and eventually feel natural.
From experience, I recommend only what is most comfortable. This is a very important point. Too many golfers read too many books and try to go out and do exactly what the words say. This is a mistake. Books can be used only as a general guide. I suggest experimenting with the three main grips: the overlapping, the interlocking, and the baseball. After trying the three, I found the overlapping most comfortable and most suitable for my game.
Stance is equally important. I instruct my pupils at Dorado Beach to keep the feet the same distance apart as the width of the shoulders. A stance like that will not restrict a full shoulder and hip turn.
When you have found your proper grip and stance, then you are ready to begin perfecting the left wall. And when you have sufficiently the wall, then it is time to adapt the rest of your game to this theory. But the wall is the key. Always remember that. A strong one eliminates the biggest problem in golf - body sway.