Work on your positioning. When you mount the gun, you want the butt of the stock against your shoulder on the torso, not on your arm. Lean into your stance, put your weight on the balls of your feet, place your feet about shoulder width apart, bend your knees. You should be somewhat square to your target, and generally one foot will be forward of the other. You're working with the gun that, as a general rule (pistol vs rifle vs shotgun), has the most energy output by far.
