Mount the streamer hook and start thread behind the eye, laying a smooth base back to the bend.
If you want the fly to ride point-up and swim with a jigging nod, seat a small dumbbell under the shank one eye-length back and lock it with figure-8 wraps, then a few turns underneath to cinch it. Leave it off for a slower, more level swim.
Tie in a full marabou tail one and a half shank lengths long. Marabou is the whole action of this fly, so take a generous pinch and do not trim it to shape.
Add two or three strands of flash each side of the tail, no longer than the marabou.
Tie in brushed synthetic dubbing or a rabbit strip at the tail base.
Wrap or palmer it forward in touching turns, sweeping the fibres back on each turn so nothing gets bound down, and stop one and a half eye-lengths short of the eye.
Dub a small, subtle wedge of a head. Keep it slim: this fly is built to slice through the water rather than push it, and a bulky head undoes that.