A rider to my #9:
Putting the gear down (before a landing on firm ground is "in the bag") is a no-no,
Only holds good for tail-draggers. For modern nosewheels, there was a discussion long ago (on Tee Emm or its postwar successor, whatever its name was). The consensus was "DOWN, BOY, DOWN" - as the modern swept wings come in at a higher angle of attack, with no wheels the tail will hit first and slam you down hard, doing your spine no good at all.
Anybody like to add anything ?