Build a smooth, tapered body with thread wraps alone. Thin at the tail, slightly wider toward the thorax. The taper should be gradual; take your time and avoid lumps.
Tie in 2 inches of fine silver wire at the bend and counter-wrap forward in 5-6 evenly spaced turns. The silver rib over the black body creates the segmentation trout look for.
Dub a tiny thorax. Just 2-3 wraps of black dubbing, slightly wider than the thread body.
Tie in a tiny white wing puff at the head, 3-4 fibers of poly or CDC. This represents the emerging wings.
Whip finish with the smallest head you can manage.