Start the olive dun thread one eye-length back from the eye and lay a smooth base to the mid-point of the shank.
Tie in a short clump of white poly yarn as a vertical parachute post at the 70% point (behind the eye). Post it upright with several thread wraps around its base so it stands as a hi-vis sighter.
Return the thread to the bend and tie in 6-8 blue dun hackle fibers for a tail about one shank length long, splaying them slightly.
Dub a thin, tapered abdomen of olive Superfine forward over the rear two-thirds of the shank, stopping at the post.
Tie in the blue dun hackle by its stem at the base of the post, shiny side up.
Dub a small olive thorax around and just in front of the post.
Wind the hackle parachute-style around the base of the post, 3-5 turns from top down, then tie it off against the post and clip the tip. Whip finish under the hackle at the eye. The white post makes this low-riding Baetis emerger easy to track in riffles and glare.
Add a drop of head cement to the whip finish, keeping it off the hackle.