I would almost rather dive at night than during the day.
The variety of fish you see is very different.
Tips, small lights are good. A sudden bright light often frightens fish and they disappear. Use the edges of the light circle.
Warning: On my last Flower Gardens trip we were told that the Grey Snapper had learned to hunt using divers lights. When the light beam would hit a butterfly fish, there would be a blur and a poof of fin, flesh, and scales as the butterfly fish became chow.
I don't doubt this is a learned behavior and detrimental to reef ecology.
Don't shine your light in your buddy's eyes. It hurts, and it ruins night vision.
Have fun night diving.
TwoBit