Mount a size 12 standard nymph hook and lay a base of black 70 denier UTC back to the start of the bend, where the barb would be.
Tail: three or four pheasant tail fibers tied in long — at least a hook shank in length. One turn, check the position, then a couple of locking turns and snip the butts.
Tie the dark green wire in along the near side and bind it the whole length of the shank back to the tail. Binding it full length is for an even body, not for weight.
Split one strand out of the green yarn and catch it in where the body starts. Lick your fingers and twist the strand tight so it wraps as a smooth body.
Wrap the yarn forward, covering the black thread with the first turn, in a single pass up to where the hackle goes, and lock it in there.
Rib forward with the wire in fairly tight, evenly open wraps — the dark green pops against the light green yarn. Take a couple of turns behind and in front, hold the thread tight and helicopter the wire off, then bury the cut end.
Hackle: a long-fibered brown or ginger hen soft hackle, tied in with the concave side toward the hook and the soft stem bent back so it locks in.
Take two wraps with the hackle pliers, preening the fibers back as you go — two wraps give plenty of fibers on this feather.
Pull the fibers back, build a ramp up to them and take a wrap or so over the fibers to hold the splay, then smooth the head and finish with a four or five turn whip finish.
Work a drop of head cement around all the head wraps and cure it for about ten seconds under a UV light.