Mount the curved hook, tie in a marabou or Z-Lon shuck trailing well past the bend.
Dub the abdomen up the curve to the 60% mark.
Stack a small bunch of deer hair and tie it in with tips forward over the eye, angled up. This forward-leaning wing is the cripple's signature posture.
Wrap dun hackle at the wing base, 3-4 turns.
Clip the hackle flat on the bottom so the rear half of the fly sinks while the wing and hackle float. Whip finish.
Substitutions
Tail/Shuck instead of Marabou or Z-Lon: Z-Lon (amber) — Sparkly trailing shuck; Antron yarn — Softer, translucent
Body instead of Dubbing to match: Olive Superfine — BWO cripple; Tan Superfine — PMD/caddis cripple
Wing instead of Deer hair: Elk hair — More buoyant; Coastal deer hair — Very hollow, great float