Night time boating is exhilarating.
Plan it carefully. All the advice above is good. Make sure the boat is rigged properly with all rubbish and lines secured. Each crewperson needs a head torch and a waterproof torch in a pocket. Lifejackets should have some sort of light attached. If cruising in company, agree a formation and avoid travelling in the other boats wake - their nav lights aren't useful to you back there and you'll kill an MOB from the lead boat. Look at ways to dim all equipment lights on your boat - everything. After a while in the dark, even switch LEDs start to seem bright. In very dark conditions, I've taken the drastic step of reducing the forward intensity of the white all round nav light by putting some tape on part of that sector. It was that or loose any useful night vision I had (there was no other traffic
Work out your passage plan using the sequence of lights you'll be able to see. It's what they're there for.
Remember to dress warm and pack everything you need so it is to hand. Aldi are selling nice red equipped headlamps this weekend.