Keep your head up, eyes fixed on the target.
As you raise your pistol, begin squeezing and let the pistol off as it comes horizontal.
With practice you can put all your shots close together. It is the most mechanical of all pistol shooting.
You get to putting shot after shot in the same place like throwing marbles into a hat.
You can test how mechanical it becomes for yourself.
After putting a dozen shots close together, try to put a dozen shots a foot higher on the target.
You will find yourself all at sea, and will have to begin aiming. Then you get so mechanical you will find it difficult to hit a foot lower, which you found so easy before.
Your arm has got so used to lifting to a certain position, your trigger finger to squeeze when the arm is raised to exactly the same position, that the whole thing becomes as mechanical and subconscious as swinging your arms and legs as you walk.
Your arms swing to exactly the same spot each time. Try to take longer or shorter steps, and to swing your arms further or less far, and you will see how mechanical your ordinary walk is.
If you want to win a prize for snap shooting, you can, by practising constantly under identical conditions of distance, shape, colour, height of target, and lighting, get so mechanical that it takes an effort not to hit the same spot continually.