Begin by locking the thread onto the hook and building a continuous thread base.  This is a basic first step for almost all flies to help lock all materials onto the hook shank and prevent twisting and spinning as you attempt to add additional materials. 

For reference – this is a T-100 size 16 hook using Uni-Thread 8/0 Black with a Tiemco ceramic bobbin.

Tie in a small bunch (maybe 20 -25 strands) of Mayfly Brown Zelon for the trailing shuck.  Leave the butts a little long to build up an underbody.  Trim the shuck about ½ - ¾ the length of the hook shank.

Twist on about 2” of dubbing keeping the dubbing “rope” very tight and compact.  Most Mayflies have a slender  body and it’s easier to build a slender tapered body with multiple turns of fine dubbing rather wrestle with a thick wad of dubbing.  The standard rule is pick out some dubbing and then cut it in half.

Here we have finished the body – almost ¾ of the length of the hook shank and tied in the Polypropylene wing.  For this size fly I typically use the full thickness of the standard carded Poly.  Bind down firmly and trim the back leaving a small wing pad.

All that’s left is to wind in the Hackle.  Here I’m using 2 Saddle hackles (Brown & Grizzly) – the brown is already wound onto the fly.  Once again, for this size fly I use about 4 turns in the space between the wing butt and 1 turn in front of the wing for both colors of hackle.  Note the space in front of the wing for the forward turns and still allowing room for the thread head.

The completed fly.  After turning in the Grizzly hackle, whip finish the head with about 5 turns and add a small drop of thin head cement, trim the bottom of the hackle flush with the hook point to drop this “Cripple” a little lower in the film and we are finished.