One exercise I like to do with new people is have them stand there and empty 2 or 3 clips, just rapid fire, one shot after another, and do it with a COMPLETELY relaxed, perfectly straight face. No lip-twitching, no blinking, no nothing. Just hold it up and go bang bang bang, appearing to be utterly bored to death. This really helps a lot of people.
I will typically follow that kind of drill with putting some kind of HUGE target, like a 24 inch circle, at 3 yards. "Just hit the circle anywhere". Then based on how they do with that, consider making the circle smaller OR making the distance greater.
My most common seen problem, perhaps like most, is muzzle discipline. If I sense that's going to be a continued problem, I quickly go to "one round only" drills. Doesn't cure the problem, but makes me feel less anxious.
Sgt Lumpy - n0eq