The hardest thing is not to "now" the shot -- a rapid press on the trigger to force the gun to go off rather than breaking the shot smoothly. This is usually accompanied by a rapid muscle twitch that pulls the sights down, coming from your subconscious.
Your subconscious doesn't like having explosions going off in front of your face, for one thing, and for another it knows that the sights are going to jump up when the shot goes off. It gets confused. It knows it's supposed to keep the sights still but it also knows that when the gun fires there's going to be a big bang and the sights will jump. So it tries to do both at the same time -- forcing the gun to go off and pull it down simultaneously. Wrong, of course, but your subconscious isn't very intelligent. Unfortunately, it also controls all of your physical movement, so there's an issue there.
Work on calling your shots. That is, you must know where the front sight is when the gun goes off. You will see it rise sharply under recoil. Where the top of the blade was at the moment of firing is where the shot went. If you can't call your shots you are not getting a surprise break with the trigger -- your subconscious is slapping it (doing a "now!"). Start by putting all of your conscious effort on watching the top of the front sight through the shot, while applying a steady, slow pressure on the trigger until the shot breaks unexpectedly. You should be able to call those shots. Once you know what calling shots looks and feels like, you can try letting your control of the trigger go back to your subconscious while still making the calling of shots the priority in your conscious mind. Ideally, you can get to the point where your subconscious is controlling the trigger, but with the goal of having the front sight in the right place all the way through the shot.
It ain't easy.
