"Grip the club as if you were holding a baby bird." ~Sam Snead
Many golfers don't pay much attention to how tightly they are holding the golf club. Many don't realize they are putting what I call a "death grip" on the club, squeezing it way too hard. They must think that the harder they squeeze the club, the more power or strength they will have. Unfortunately, the opposite is the case.
Squeezing the club too hard increases pressure in the hands, arms and upper body. The increased pressure restricts movement. The tightness decreases the amount of wrist cock/hinge, and restricts the flexibility of the shoulders and upper body. More often than not higher pressure results in distance loss and often times block cut or slice to the right.
Obviously one needs to hold the club firm enough that it doesn't fly out of your hands during the swing, but try to hold the club with relaxed pressure. Being in a more relaxed state will increase flexibility, club head speed (thus distance) and accuracy.
Think how smooth and relaxed Sam Snead looked in his golf swing. Light grip pressure is where it started with Snead.