Great advice by all. I really started shooting better when I did a few things different. First, have the same grip each shot. Fine tune your draw by adjusting your release. I Anchor with a nuckle under my ear and into my jaw bone and my nose on the string. I want my trigger finger in front of the trigger and wrapped around it just barely touching. If I get on the target and am ready to shoot, then move my finger, that micromovement will ruin the shot. When I draw, I want my bow sights above the target, I find my anchor, breath slowly, level my bow and lower my bow slowly to the correct pin. I find it is easier for me to lower the bow and hold steady, than to raise the bow and hold steady. Once on the target, I still continue to breath. I read once, that after 7 seconds with not breathing the body will begin to fatigue in the form of small shakes or micro movements. I also use mostly back muscles to hold the bow and to release. Just before release, I think " follow through" and don't try to see the arrow.
I know if you have a Pro watch you shoot, you will pick up some good ideas. A couple more ideas. Shoot longer ranges - ranges where you fear of losing an arrow, this will make you focus and concentrate on good form. Shoot 10 good arrows, only 2 at a time in 5 sessions at 50 to 70 yards. Using good form and working on your technique this will really tighten up your groups at 30 yards and in. Next, don't overshoot. When you get fatigued, that is when bad things can creep into your shooting. When I am training for a shoot or for season I will end my shooting session with this exercise. I move up to 30 or 20 yards, draw the bow and then hold it for 2 minutes at full draw. I concentrate on breathing and using the correct muscles, and at 2 minutes then I start to shake. I then concentrate and settle that pin on the target and make a good shot. I pull out another arrow, draw and hold it for 1/2 as long, then make a good shot, then do a 3rd arrow for 1/2 as long as the second and then shoot a good shot. This will really condition your muscles. Don't start out with 2 minutes unless you shoot alot. Start with what is right for you, and then increase as strength increases. Hitting the gym will help as well. Best of luck.