SecondChance

I would have to say that it will begin with a mental regime before physical. Reason being.
What is your archery experience up to this point?
Do you gorilla grip the grip or just gently grasp/cradle it prior to shot?
Are you fresh for the day or trying to shoot after a hard days work and just beat?
What release are you currently using?
Set up a video camera and video yourself during a shooting session and watch it afterwards. You will find out exactly what you are doing during the shot.
Set up a shot sequence. My old shooting coach had me set up with a 9 step process.
1. Hand into wrist strap. Relax.
2. Nock arrow. Relax.
3. Place release on D-loop. Relax.
4. Lift bow arm. Relax.
5. Draw with open hand. Let bow find natural pocket in hand and stop with release hand knuckle locked onto right ear lobe behind jaw bone. Relax.
6. Settle string on tip of nose while focusing on target thru peep sight. Relax
7. Remove trigger finger from behind release trigger and begin to settle on trigger while applying pressure for shot. Relax.
8. Settle finger on trigger in crease of the 1st knuckle, not the pad. Relax.
9. Settle pin on target while continuing to apply pressure on trigger as it floats onto/across the target for a surprise release/trigger break. Let bow flow out of hand allowing the wrist strap to capture the bow upon release.