One of the most common-and disastrous-swing faults that I see with my students is re-gripping the club at the top. When you re-grip the club, you allow your fingers to loosen on the club as you near the top of your swing. Then, as you transition from the backswing to the forwardswing, you tighten your grip with your fingers-and usually cast the club over the top of the proper swing plane.
Bring it down steeply to the ball on an out-to-in path.This move usually results in a weak slice or a pull-hook, depending on the angle of your clubface at impact.
If you have a tendency to re-grip the club, make this slight adjustment to your grip: instead of resting your thumbs to the side of the club, place them directly on top of the grip. Your thumbs will keep your club securely supported at the top of your swing, and you'll find it much easier to maintain an even grip pressure throughout the swing. An additional benefit is that many players find that the additional pressure points of the thumbs on the grip of the club allow them to more easily release the clubhead through impact.
"Re-gripping" the club at the top of your swing is a disastrous swing flow that can produce a wide variety of mis-hits.
To avoid re-gripping position your thumbs so that they lie directly on top of the grip. Your thumbs will support club at the top and you'll have a much more secure grip. With your thumbs on top, you might even find it easier to release the clubhead through impact.