Fault: You're hitting weak pulls off the tee and not generating enough power because you're releasing the club too soon in your downswing.
Fix: This drill teaches you to swing your arms down without prematurely releasing (casting) the clubhead. Take your driver to the top of your swing with just your right arm. Hold a small plastic bottle against the right side of your torso as shown, then bring your club down to impact. If you can squash the bottle before you unhinge your wrists, you're delaying your release until the moment when it creates the perfect blend of power and accuracy. If you can't, you're allowing the clubhead to outrace your hands to the ball, which costs you in yards and missed fairways.