If you don't know what depth, it can be frustrating. On the other hand, a slight mount in on one side of a bed can act as a magnet for every fish in the area not actively hunting. Find an area with several of these mounds and you've got your honey hole. Depending on the local botany before it was flooded, you may be able to spot these mounds by looking for a specific type of tree which grew only on a mound or down in a cut. A perfect example is willow trees that would tend to have grown lower and closer to the water level of an old creek than say the surrounding oak trees.
Cypress trees are another sure tip off of a change in structure level.
You'll read many times about a tournament won fishing a specific type of tree. More than likely, it wasn't the wood type that made the difference, it was depth that type of tree was growing in before the lake was built. We've now established looking for a structure with cover, it's time to chose amoung all structures with cover that ends at the structure edge. This will depend on several variables, water clarity, weather, season, statification, temperature, etc. We could try to consider everything, but for starters, there is an easier way.