I learnt of this technique from a member of the disciplined forces. To maximise your accuracy when you are aiming at a target, first aim your gun and breathe in. Then breathe out. As you breathe in again, concentrate and release press the trigger. The trigger should be released before you complete breathing in. Anyone tried this technique?
To be honest, I am not a user of gun but I have to admit that I have tried using the air gun. My father-in-law was a good hunter and also a champion target shooter (his trophies and medals speak for this). When he sees a gun, he had the tendency to be like an instructor. I have heard from him several times the proper way of shooting. With the rifle, press the butt to your shoulder then rest the finger in the trigger while you look for the target. When the aim is right, you hold your breath then aim again before pulling the trigger slowly. That's what I learned from him although I cannot vouch if I had done it correctly.