I'd read the manual first, and on top of that get what info you can on the particular systems you're interested in on that airframe, ie the gear actuation system and the CSU with emphasis on what can go wrong with them.
Identifying failure modes and what the emergency checklist says to do about them wouldn't be a bad start.
I haven't flown the retractable Cessnas but there'll likely be a normal way of getting the gear up and down and something else to do if that doesn't work!