There are a few tips & training methods that can assist you;
Learn proper methods & train using them during practice. As a cadre told our MP school class, don't just shoot, use the proper training. It will become second nature.
If you can, train or shoot w/o distractions or other shooters around. If you can shoot on a gun range or rental place, go during the off hours(weekdays AM or early afternoons). Noise or people talking may cause you to lose focus. Learn to concentrate and build your marksmanship. If you are in a remote area or have a large property, you can train without hassles or safety issues from strangers.
Learn to fire after you exhale. Take a deep breath, slowly let it out, then fire.
Finally, I'd read up on a few books or guides from top shooters or LE sources; No Second Place Winner, Hit The White Part, etc; www.paladin-press.com