I'm going along with all of the others on here and saying to dry fire. You may know that there isn't a round in the chamber, but you're still practicing your finger muscles to move independently of each other.
Another idea is to practice dryfiring at the range. Shoot about five shots. When the slide locks back, bring it forward again and pretend that you're shooting. I've done this last time I was at the range and I could tell that I flinched a little bit. After dryfiring a few more times and inserting a fresh mag again, my groups improved. I was even able to make a three-shot group about the size of a golfball once at 25 yards with my 9mm. There was probably a little bit of luck involved there, but I'm sure the practicing had something to do with it.
If you still can't get over knowing that your gun isn't loaded, maybe you can insert a snap cap or two randomly into your magazine. You won't know if it's loaded and you will be able to tell if you have a flinch when the gun doesn't go bang. This method obviously requires you to be more careful since you don't know if there was a primer malfunction, but if you follow safety rules, you can still be safe doing this.