I won’t overload you with Bug terminology. I would only be borrowing from more accomplished researchers. You can find plenty of excellent work by Rick Hafele, Arlen Thomason, Troutnut.com……. You do the research on the several varieties and shapes of dragon fly nymphs in the (Anisoptera > Aeshnidae (darners) > Libellulidae (sprawlers)) world.
Many fly fishing dragon patterns will be longer, size 6-8 patters (more the darner variety). But there is a place for the smaller size 10-12, shorter and rounder patterns that slowly move about the bottom in the vegetation and muck and only rarely jet forward. A slow and low presentation is appropriate for stillwaters and quite backwaters of streams (some varieties of Dragons do inhabit slow moving stretches of rivers).
The above pattern was tied on a size 10, 2xl nymph hook. I dubbed and spun marabou fibers stripped from the stem. Once the density is developed for each color then the marabou is trimmed to shape the bulbous rear, tapering toward the front. At the front of the abdomen, I dubbed in some deer hair and then wound the hen hackle. The head is comprised of red dumbbell eyes (melted red Amnesia mono for eyes) the wingcase is a small piece of fuzzy foam tied in at the front the eyes. The head is dubbed to form a nice round head. Then the fuzzy foam wing case is pulled over the top of the head and tied off to form a slight gap between head/thorax and the abdomen.
The presentation of the dragon fly nymph along the edges and drops of a lake should be more thoughtful than kicking along in a tube trolling a Woolly Bugger or Dragon nymph imitation. This is the primary reason you should study how insects move in their world. Study the predatory ways and movements of insects and then attempt to visualize this and match this with retrieves and assorted fly line densities. Most often dragons will crawl up vegetation, rocks and debris to emerge above the water. Some are poor climbers (squatty little gomphids) and crawl into shore.
This isn’t like trying to match the Stonefly hatches where you fish nymphs and then post emergence, fish dries. Dragon fly dries are seldom used. You want to focus on where dragon fly nymphs reside and then go there and present hunting nymphs and nymphs working toward structure to emerge.