The kinds of mistakes will vary depending on what part of their training they are at.
Pre Solo
- failure to maintain the correct attitude for the phase of flight
- forgetting to trim or trimming too much/not enough
- not keeping the circuit square
- pumping the elevator in the flare
- looking straight over the nose in the flare
After Solo
-over priming hot engines
-poor airmanship on the ground (not on taxiway centreline, controls not positioned for wind, especially when turning, not watching where prop blast is going
- concentrating on the wrong thing (like immediately answering a radio call when they should be concentrating on flying the aircraft)
- rote patter on the checks without actually performing the action
-not monitoring the engine instruments in flight (a personnal pet peeve)
-rushing through manoevers without letting the airplane settle down first ( example: unstable entry to a steep turn = poorly done manoever)