It s in the daytime you can best learn all the idiosyncrasies of the structure - the points, the sunken islands, the inside turns, the rip rap and how it s laid in there. Nighttime fishing is shallow fishing. You are going to be working in 15 feet or less. It s a dangerous time to learn about submerged hazards. Consider using glow in the dark marker buoys or ones with lights attached to help follow contours when you return later.
Homework done, the real fun begins when the sun goes down.
Begin at main lake points that go all the way from the shoreline to deep water. If there are fish on them during the day, even more will be there at night. And, the bigger the structure, the better. Bigger structure holds more fish. Use your sonar to look for fish.