Set your right arm at the top for booming tee shots.
You can fix a lot of your driving problems by getting the club set correctly at the top.
To accomplish this, you need the correct blend of width and depth in the backswing. Width means how far you extend your hands away from your chest. Depth means how far to the inside you move the club. You can monitor both by focusing on the position of your right forearm (for righties).
For good width, swing to the top so your right arm folds into an “L” [above]. If you go past the “L” position, you’ve lost your width. For depth, get your right elbow pointing down at the top [left]. If the elbow juts out and points behind you, your hands are too far inside. Getting your right forearm roughly perpendicular to the ground from both angles will give you the perfect mix of width and depth. Then you can be an athlete and just rip it.
– with Peter Morrice