A river hands you the answer - current shows you the seams and lies. A lake hides it. There's no flow to read, so you read two things instead: structure and depth.
Structure is any edge or change a fish relates to. Cruising fish use these the way you'd use a hallway. Hit these first:
- Drop-offs and shelves - where a shallow flat falls into deep water. Fish patrol the lip.
- Weed beds and weed lines - the outer edge is an ambush wall and a bug factory. Callibaetis and midge hatches load up here.
- Points - a finger of land sticking into the lake funnels cruising fish past the tip.
- Inlets and outlets - moving water brings food and oxygen. Always worth a look.
- Submerged structure - rock piles, sunken timber, old creek channels. Cover for bait, ambush for predators.
Depth is the other half. When water is cool - early, late, spring, fall - trout cruise and feed in the shallows. In summer heat they slide deep where it's cooler. Adjust how deep you fish, not just where.
The big difference from a river: the fish is moving. You're not casting to a fixed lie - you're casting to a lane a fish patrols. Watch for cruisers and rises, then lead them: drop your fly, lure, or bait a few feet ahead of the path so it arrives as the fish does.
Three places to start, in order: inlets, drop-off edges, weed lines.