I do about 15 million walk throughs on every stage. This really helps me. I view shooting as an individual performance like public speaking. No-one wants to stumble or stutter over their words. Everyone wants to impress the crowd and look their best. Its just human nature. So I look at the walk through as learning my script on the spot and practicing it as many times as I possibly can to figure out what movement I can eliminate, what might look/feel more smooth, etc. I'm not a "great" shooter by any stretch but I usually come in anywhere from 5th to 10th at any given match multigun or pistol. I usually focus on shooting a clean match without few penalties even if my times aren't blazing, and that relaxes me as well, along with the fact that I'm doing something I really enjoy.
-V