Mount hook, tie in 6-8 dun tail fibers, one shank length.
Dub a slender body to the 70% mark, half the dubbing you think.
Align the tips of 2-3 CDC feathers and tie them in as an upright wing, about one shank length tall. The CDC needs no hackle. Its own structure floats the fly.
Small head, whip finish. Dress it with powder desiccant only. Gel floatant destroys CDC.
Substitutions
Wing instead of CDC feathers: Snowshoe rabbit foot — Similar flotation, easier to handle; CDC puffs (pre-formed) — Faster to tie than whole feathers
Body instead of Dubbing to match: Olive Superfine — BWO match; Gray Superfine — General mayfly; Tan Superfine — Caddis/light mayfly