Here is a simple drill to help you hinge your wrists.
Place a tee in the butt end of your club. As you swing back, your wrists should start to hinge so that about three- quarters of the way-back position is where your arms and club forms the letter “L”. The tee should be pointing down to a spot on your target line. If the tee is still pointing at your belly, then you may have to hinge the elbows instead to complete your backswing – losing valuable width and extension.