Although I was kinda joking earlier, I was also serious. Some of us have to warm up those muscles and stuff before our form will settle in and the arrows will straighten out and fly right.

Something I do might help. I'll draw to anchor, concentrate on a spot and hold for a count of 10 before letting down. Doing about 10 reps of that gets the arms and back warmed up and gets my concentration grooved before I ever release that first arrow.