First you need to learn the proper trigger pull. And snap caps relieve the stress on the firing pin when you are thus snapping-in.
Snap caps also allow you to test a magazine and how the slide is feeding on your pistol, without using dangerous live ammo.
Snap caps also allow you to practice your draw and shoot. This needs to be done in front of a mirror, about 20 times a day, every day, until you get good at it, perfect in every way. Snap caps protect your firing pin during the drill.
You need a firearms coach.