A wider swing equals
more power. To create maximum width -- the distance from
the butt of the club to your left shoulder at the top --
set your wrists early in the backswing. How early? Both
wrists should be fully hinged by the time your left arm
is parallel to the ground.
To feel an early hinge, try this. With just your left
hand, grip down a few inches on the club. Swing your
left arm back until it's parallel to the ground and then
add your right hand. Your wrists should be fully hinged,
the left forearm and clubshaft forming a right angle.
Strive for this feeling in your normal swing.