The single most important thing, from a practical point of view at least, to teach in night flying is not to use the landing light to judge the flare!
Couldn't agree more - the first thing to teach a student when landing at night is NOT to look at the runway - look all the way down the runway and judge height from peripheral vision of the runway edge lighting - this height /vision will have been demonstrated prior to departure by sitting on the numbers for a few minutes pointing out all the lights and what everything looks like at night to them.
I think landing at small airports is harder than at major intl airports as places like Heathrow, Gatwick, Luton etc are lit up like a Christmas tree - go to some small airports and the runway is a like a dark black hole with limited lighting.
On the same note, ask ATC to turn the runway edge lights down to their minimum brightness, and turn off all other runway lights (approach lights, PAPIs, etc) when teaching night landings to a new student.
Not always possible - some airports say they become unlicensed if they turn off approach lighting.
(There is no need to teach navaids, since the student should be familiar with them from his PPL anyway
Not in my experience - I currently teach a vast experience range for night and IMC and the majority of PPL holders haven't a clue how navaids work - they are more familiar with the 'direct to' of the GPS which of course gets switched off. Basic instrument flying and navaids becomes a brief of its own.
Personally, I think five hours for the night qual is not enough - too much to cover in too few hours and there is commercial pressures to keep it to five hours because that it what the student will have paid for.