Have a flashlight handy for use in the boat. Have all your gear organized for easy access. Wear your lifejacket. Remember, the more organized you are & the less noise you have to make to reach everything you need ... the less chance of accidents, or spooking the fish. Don't wear cologne/aftershave or use scented soap, and have some bug repellent handy. But, understand ... bug repellent is only going to keep most "biting" bugs away. The "other" bugs are drawn by the light, not you, so they're still going to be a nuisance at times.
Hang light over side of boat & set up your fishing equipment before dark, once you've reached the spot where you want to start. Anchor or tie off to a standing tree in deep water, or off a point, or near a well lighted dock, or in front of a logjam in a main lake pocket. If you haven't started getting any baitfish circling around the light or any bites within an hour after dark ... you probably need to move to another location. If the moon is up & visible, try to locate a spot where the surrounding hills/trees block it from shining on the bank/spot you're fishing.
Set your poles to fish mostly on the outer fringes of the light, but don't be afraid to fish some of them directly under the light. Set your baits at varying depths to start, then occasionally change them shallower/deeper until you start seeing a pattern of depth & location (in relation to the light). That is if you're using minnows. You can also cast jigs well out past the outer reach of the light, and slowly reel it back into the light. That also works when casting jigs around well lit docks, or docks with big lights hanging off the side & pointed towards the water.
Make sure you have a dedicated battery for the light to be hooked to, as some of them can draw a battery down over several hours of continuous use. If you don't have a marine grade jumper cable on board ... I'd consider using the trolling motor battery, rather than the starting battery, so you can at least get back to the ramp (without having to switch battery cables).
It may take you a few trips to iron out all the kinks & configure/reconfigure your setup to the conditions & to your liking ... but, once you get the hang of it, it's a good way to catch some fish & beat the heat, all at the same time.
It probably wouldn't hurt to have a lantern or some other light source to put between you & the rods, just to provide light enough to see your rod tips. A 9V battery operated lantern works fine, but if it's open 360deg .... open it up and put foil around one side, or tape foil around the outside of the globe to deflect the light from shining in your eyes. They also come in handy for seeing floats, if you happen to like using them. White styrofoam floats can be seen a fair distance from the boat, and more easily than the colored topped ones (and much cheaper than the lighted ones).
Have a good landing net handy & close ... as Crappie are not the only fish that may be attracted to your baitfish buffet !!
Crappie can be active all night long, but are usually more active right before dark & shortly after dark ... then again just before daylight. If you're set up & fishing before dark & not catching fish by midnight or so, even after moving around to several different spots, call it a night & try again another time.
And let me emphasize something important ... WEAR YOUR LIFE JACKET !! I can tell you from experience, that it only takes one false move & about 1.5 seconds to find yourself over the side of the boat & under/in the water !! Think SAFETY FIRST, even if it means messing up your fishing spot ... you can't "try it again, another day" if you drown !!
... cp