Opening and closing the face of the club too much during the backswing and downswing will cause you to hit the ball with the toe of the club
Setting up too high or tight with your left arm and shoulder leads to injuries, as well as a flat shoulder plane and over the top swing
This drill is great for people stuck in an office or in bad weather, hook the right hand under the left and practice your backswing and downswing with a perfect right and left wrist position