A few points that always kept me safe while teaching multi and I thought was very effective in the teaching process.
- In multi-training, never surprise your student or they will surprise you.
- no need to pull mixture to simulate an engine failure, I always used throttle. You never know when you will need that power.
- I always demonstrated an engine shutdown in flight (power,prop,mixture). Always above 3000' and let your student fly around a bit so as to get the feel of real single engine flight with a fully feathered prop and to gain some confidence.
- I can't emphasize enough giving you student a good briefing before you lesson on what you plan on doing and what you plan on accomplishing. This will keep it safe. Pulling the mixture after rotation at 300' with a novice multi-engine pilot and watching to see if he screws up may be hazardous to your health.
Keep it safe.