The secret to a good swing is synchronizing the movement of the arms and club with the pivot of the body. Many amateurs get out of sync from the beginning—and never recover—because they whip the club back with their hands and arms only. The first three or four feet of the backswing should be controlled by the body pivot. You can see here that I haven't hinged my wrists yet. I'm simply coiling my upper body against a stable lower body. The triangle formed by the hands and arms moves in tandem with the movement of the upper torso.
If your swing feels out of sync, lighten your grip pressure and initiate your backswing with passive hands. Let your body coil control that first move. You'll know you've got good synchronicity if your club arrives at the top at the same time your body stops turning.
As a rule, your grip pressure should be light. But there are times when you have to hold the handle a little firmer. Out of thick rough, grip tighter with your left hand to prevent the clubface from closing when the grass grabs the hosel at impact. Same is true when your ball is buried in a bunker.
David Leadbetter, a Golf Digest Teaching Professional, operates 26 golf academies worldwide.