The best areas are rip rap areas with a lot of rocks, like dams, bridge pilings, and rocky bluffs. But shallower gravel flats can also be good. I like 10 - 25 foot depths best, no matter the time of day or year. Though I would try closer to 10 - 20 during prime evening bites.
Catching walleyes during the day seems to just be about moving. Spend about 5 minutes per hole, and if you don't see any fish on the flasher or get any hits, move again. Daytime walleyes don't move much. They know they have a vision advantage over their prey, so they know they can wait till evening to get a good meal.
Tyler