As with any sport or hobby, the only way to improve is to practice the sport.
Nothing can replace the mundane repetion of a baseball players batting or fielding practice.
But that practice must be done in a manner that will correct poor habits. If you are pulling the trigger wrong, flinching, not following through on your shot, then nothing can correct it but you. If I might suggest, a shooting buddy can assist one greatly. Both can provide observation of techniques and help each other to become better shooters. But this sport provides one to be able to practice just about anywhere.