It really depends on the lake. Is it stocked? and when? Recently stocked lakes have trout everywhere as you can imagine. Lets say 2 weeks from now, some sunny days, and you can expect them to be near the shoreline lookin for bugs but near dropoffs. 10-15ft of water dropping off to 25-30. They are predators and i suppose they may ambush at some time but mostly they cruz the shallows until the temp rises. But some lakes concentrate fish in 25-30ft of water. And i've caught trout while bassfishing in and around big fallen trees jiggin half a nightcrawl and a tiny weight. I often resort to jigging a nightcrawler in 20ft of water off of shelves after other tactics fail. It seems to always work. So they must be holding or cruzing just above the drop. Fish feel safer when they have quick access to deep water. So i'd say a big sunken tree or weeds in 20ft of water near shore next to 30ft of water would be an ideal spot.