The most common causes of hooking (too much right to left curve on the ball) are a closed club face at the top of the back swing or a bad grip or both. Usually a closed face at the top of the swing is when the back of the right hand is facing the ground when you grip the club. You need to cover the thumb of the left hand. That will keep your right hand working with the club face. The left hand turned too far to the right can also close the face. The club can also get closed at the top of the swing by permitting the left wrist to collapse into a reverse cup position.