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. If you don t see any, move to your second spot, then your third. Keep moving and looking until you find a concentration of walleyes. I could have the best spot where I caught 30 fish the night before and go the next night and not see any fish. Most people I know would just go right on fishing it.