The key technique: tie in 4-6 white saddle hackle feathers FLAT, horizontally, not upright like a traditional streamer wing. The feathers should splay out to each side, creating a wide, flat baitfish profile.
Tie in 2-4 olive or gray saddle hackle feathers on top, also flat. These create the darker back.
Add 6-8 strands of peacock herl as a topping for dorsal color and iridescence.
Add sparse flash, just a few strands along each side.
Build a neat, smooth head. Whip finish and cement heavily. 3-4 coats. These flies get thrown hard.