Not a flying instructor but used to instruct diving to mixed gas level for a few years.
Good technique I always found when trying to teach a particular drill is not to teach it all in one go but to break it down. We used to try and break a task down into about 5 steps from start to completion - found students used to pick things up a lot quicker rather than trying to do everything at once and mucking it up! Once they know what they are doing they will naturally become less mechanical about the drill and perform whatever task is required of them.