Not specific to Aztec, as I have very little Aztec time, but just a couple of general things which I wish I'd known before I did the MEI course:
Know the difference between EFATO, engine failure in the cruise and engine fire drills.
Understand that, when asymmetric, every single power or speed change will require a change of rudder trim. Practice this in your flying before your MEI course.
And one more for after you finish the course once you start instructing: when actually feathering an engine, always do it at the end of the flight, not the start. That way, if the engine doesn't start again, you don't have to throw away the rest of the planned flight.
FFF
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