If you don't pick a spot and concentrate on that one spot you will shoot over the back every time. I should know, I missed the first 9 I ever shot at and every one was over the back.
About a month before the season starts I try to do everything I would do when shooting at a deer. ...from an elevated stand, pick a spot, slow purposeful draw, pick a spot, come to anchor, pick a spot, and a smooth release...and don't forget to pick a spot and KNOW your arrow will be there shortly!!!