In shallow water, like water depth less than 6 ft., I like Dahlberg divers. They're a nice water pushing fly that you can start out fishing on top like a popper, and then they get soggy and work subsurface. They even float for a while with a sink tip line.
I usually like to trim the fanned out deer hair back a bit on the body. Tied on a good size hook, otherwise the little bass and sunfish are all over it. The smallest hook size I use is #4, on up to #1/0. I like white ones or black ones. A soggy trimmed Dahlberg Diver on a sink tip is a good shallow water leech imitation.
I've read that mature smallmouths are sort of territorial- in northern lakes, one good-sized fish stakes out around 50 yards of rocky shoreline as a feeding ground, up to about 50 ft. out from the bank. Bass like to cruise for their meals in shallow water. If you see a school of minnows causing commotion, most often they're being pursued.
In the summer, The best times are always early before the sun hits the water, and again at dusk. I always have the most fun catching them close to the shore. Rocky points and clumps of boulders.
I use regular leech patterns, too. I like black Slumpbusters the best. Rabbit flies. They have good action. Tied on a tandem hook, around 4" long. Don't use more weight than you have to. In less than 10 ft. of water, no need for dumbbell eyes. Use a fly tied with a smaller metal conehead instead. Use the least amount of weight that works to get the fly close to the bottom. It's no fun throwing heavy weight with a fly rod, and it messes with the action of the fly. You want them to push some water and swim. The heaviest leech flies I have, it really makes more sense to cast them with a spinning rod, or troll them in deep water.