Pet hates as a student
1) Aeroplanes that, while they are technically serviceable, are scruffy, dirty, smelly, damp and with bits falling off and inop systems.
2) Training sorties without a clearly defined purpose. This is exacerbated by a poor preflight brief.
3) No post-flight debrief. There is always something to go away and think about. Get the brief and debrief right, and the student will get the best value for money.
4) In-flight feedback. A bit of advice / encouragement / positive comment really helps.
I guess the last three points are all about the communication, which is a two way thing. The instructor is senior so should be following a clear structure and leading by example.