Another tip you can try is to close your eyes, then draw and anchor the string or any other contact anchor point. You will feel that jittery feeling for those few seconds, but while your eyes are closed your uncontrolled desire to touch the trigger should be lite or nonexistent. When you have calmed yourself and feel the powerful confident feeling, then open your eyes. You may need to adjust your aim a bit, but that need to send the arrow should be under your control. Use small sticker dots on your target and stand at the 20 yard line to practice. Aim small, miss small. Aim big, miss big. Focus on hitting that tiny dot, not hitting the whole target. You can also decrease the size of yardage pin diameter. If the pin is giant and a glowing star when you are trying to aim, you may get that "close enough, fling it" feeling. If your pin is a tiny little spec you wont cover much of the bullseye allowing you to really pin point place your pin on that small dot sticker. If you have a sight that has multiple pins you may consider changing to a single adjustable yardage site. I am fond of HHA sights. If you are looking at four pins and they are all on the target that might trigger the "close enough, fling it" feeling. While perhaps a single pin forces you to focus on one pin on your target dot.
Take it one shot at a time. A nice smooth draw. A closed eye anchoring of the string....and relax. Pick your point of impact, make it a tiny spot. Then follow through with your shot.
I hope this helps, I had the same issue. And once in a while it comes back. I do this closed eye routine to force myself to wait. I found that with my eyes closed, I cant see my target but I know its there. With closed eyes I felt as though it was impossible to release the arrow. After several seconds of quieting my mind, when I opened my eyes I started feeling like I could hold the shot until "I" was ready.
Good luck to you this fall.
Whitetail Strategies Guide Service
Fred Scott