Here's a good technique that really works. Have your shooting buddy load your gun with a mix of live ammo and empties. Shoot the gun while watching the front sight very close. When you snap on a dud, the barrel will do some tricks. Most shooters anticipate recoil and try to push the muzzle down at the moment they squeeze the trigger. Swan dive! Finger placement on the trigger will do some nasty stuff. Too much finger will cause the muzzle to move left (right handed shooter). Try centering your finger print on the trigger. Practice dry firing with a consistent hold and trigger finger placement. Cock the gun with your non-shooting hand to maintain a good hold.
Even though it seems instant, there is a period of time required for the hammer to fall, the primer detonating, powder to burn, and finally the bullet goes zooming out of the barrel. Any gun movement during "lock time" will certainly make the bullet hit somewhere other than the bullseye.
For bench shooting, the worst thing you can do is to let any part of the gun or your hands touch the bench or sand bag. The best stance is holding the gun with both hands and resting your arms, just behind the wrists, on a sand bag. Lay the gun down after each round. This forces you to pick it up and renew your hold. If you try to shoot multiple shots without setting the gun down, you'll find you are moving your hands but not really adjusting for the same hold every time. After considerable practice, you'll find the right hold quickly and won't have to set the gun down.
Shoot light target loads. They make less noise and recoil. When you can put out the lights with target loads, move up to something a little heavier then finally you can shoot magnums without flinching.