Within a specific range of sizes and actions, plastic worms are the most versatile and most effective tools to use for smallmouths in lakes. The right worm is 4 to 5 inches long and relatively thin.
Smallmouths often suspend over relatively deep water in reservoirs and natural lakes in summer, when baitfish populations peak. In reservoirs, they tend to follow shad or shiners.
Smallmouths can winter deep in reservoirs, down to 50 feet or deeper. Wherever 50-foot flats exist, that's where they'll be whether it's in a creek arm or the main reservoir.
It's typical to have smallmouths congregate on humps and sunken islands that top out at 15 to 25 feet deep during fall in natural lakes.