By keeping the clubhead off the ground instead of soling it at address, your whole body stays activated as you get ready to start the backswing. I call it being "locked and loaded." Grounding the club can cause you to tense your body slightly and snatch the club away with your hands. Hovering keeps your tension level constant and helps you start the club back with good rhythm.
SOLID IS THE KEY
During the swing, I don't have actual thoughts so much as an image of making contact exactly on the sweet spot of my driver. Solid contact is more critical to maximizing distance than raw swing speed. Drivers today are more forgiving, for sure, but they still pay off best when you find the center of the clubface. When you play—and practice—focus on hitting the ball flush.
KISS THE SHOULDER
If I turned my shoulder under my chin like some teachers say, my swing would be too upright. My swing thought is, Kiss the shoulder. I have a perpetual case of chapped lips from friction with my shirt, but it's worth it. It guarantees a full turn and serious clubhead speed through the ball.
LET YOUR HEEL COME UP
Don't follow the trend on tour of keeping your leading heel glued to the ground. The "resistance" could cause you injury and actually cost you distance. Let the heel rise. You'll make a bigger move behind the ball.
KEEP THE FACE SQUARE
In all of 2011, I've hit exactly one draw off the tee. A fade is more accurate and goes almost as far. The key to a monster fade is to not let the clubface rotate closed through impact. Try to keep the face looking at the target after the ball is gone.
My follow-through is often less than picture-perfect. In this photo, I'm hanging back on my rear foot, which is unconventional but shows that I tried to stay behind the ball to hit it high. Because I hit a lot of different shots—big fades, high balls, low screamers—I make some unusual finishes. As long as I hit the ball solidly, I'm OK with a weird-looking finish.