Train train train. By that I mean get training. At the least take some NRA one day courses as you can afford them. There is someone nearly everywhere offering the courses. A longer course at one of the well known schools is great if you have a few grand for it.
Learn SD law - many community colleges offer police science classes, some of those may be helpful. I took a couple a long time ago. I've been watching for something locally.
Practice, practice practice. Until you can hit what you shoot at, until you can shoot and move, shoot while moving, etc. When you feel confident of your abilities you will not only feel better but you will Be better.