Not all ways to kill you but a couple of these could prove expensive
Whilst teaching relationship between correlator,throttle and power - ie constant RRPM at different power settings- student opening or closing throttle too much.
Similar problems in Gov off exercises during take offs, landings and circuits.
Getting confused and believeing RRPM during auto will be increased by raising the lever

Particularly on extended range autos
Allowing the nose to drop whilst auto is entered - the subsequent attempted levelling being over corrected to create a massive flare.
Harsh collective (snatching and dumping) for Take offs and landings, particularly during sloped ground training.
Hyd's off training when you first teach that.
Allowing the nose to drop mid turn during downwind quickstops.
Student on supervised solo flight starting aircraft with throttle open

(I hasten to add not one that has happened to me - touches wood rapidly- but was a problem for YOUR favourite coastal training provider a few days ago when a/c was started with throttle fully open!)
Hope the course is going well