A tension filled grip, especially from having the shaft too much in your palms, will kill your entire swing. It stops your wrists from hinging naturally and then works its way up your arms and into your shoulders and locks up your entire swing.
Practice making half swing with this pen drill to maintain a constant distance to the ball throughout the swing
Develop control and feel for pitching distance by creating a set position on the backswing as your benchmark and then vary your shot distance by the power you swing with