I did some night flying earlier last month. I loved it, in fact I prefer flying at night than during the day. Anyway, my advice comes from that personal experience - and this is "Make sure your instrument lights - work adequately and carry 2 torches."
That might sound a bit of a no-brainer but here's what happened.
My instructor and I took off on a sunny afternoon, (yes we do get the occassional one in Scotland) for the outbound leg of a night cross country. During out pre take-off checks we had checked all the lights and they did work. However, on the way back when it was dark, we discovered that the instrument lights were pittyfully weak. Something we hadn't noticed when checking during daylight.
Anyway, my instructor produced his mag light which decided it wasn't playing ball, luckily I also had mine so I was still able to read the map and log.
Since then I have also invested in those red filters you can get for the lense of your mag light.
Sorry if that seems a bit obvious.