Friend and fellow New Jersey fly tier Matt Grobert introduced me to this type of soft hackle a couple of years ago. Since then, they've become one of my favorite all round patterns to fish.
During most of this year's sulphur hatch, size 14's like this one did just fine but later in the hatch, when the trout got fussy, switching over to a slightly lighter and smaller version really worked wonders.
For the smaller version, a size 18 Dai-Riki #300 Dry Fly hook is a good choice. Start by mashing the barb and getting the hook firmly secured in your tying vise.
For thread, I like UTC 70 Denier in a color they call Wood Duck but you can go with standard brown as well.
Start your thread on the hook shank leaving some space behind the eye and take wraps rearward before snipping off the tag.
To add segmentation and increase durability, I like to incorporate a rib of extra-small gold Ultra wire. A 4 or 5 inch piece will make several flies. Secure the wire to the hook shank and take thread wraps all the way back to the bend.
To create a lighter colored fly, you can use a pheasant tail feather that's been dyed yellow, as I'm doing here. Pull down 6 or so fibers perpendicular to the stem and strip or snip them free. Measure the fibers to form a tail about a hook shank in length and then, with a pinch wrap, tie them in right at the start of the hook bend. Two to three wraps of tying thread ought to do it. Now, without advancing your thread, begin taking wraps around the hook shank with the fibers. Leaving the thread in this position helps to keep the fibers from separating. Tie off the fibers where you started your thread on the hook shank and then snip them off close.
Get hold of the Ultra wire and begin making open spiral counter wraps to segment and reinforce the pheasant tail body. To securely tie off the wire, take a thread wrap around it to change direction so that you're making counter wraps with your thread. After a few of these, once again, use the wire to change the direction of thread wrap back to normal. You can then helicopter the wire to break it off close.
For the thorax of the fly, yellow rabbit fur works well. Just the smallest pinch is all you need. Matt touch-dubs the rabbit fur on but I prefer to use the split thread method. First spin your bobbin counter-clockwise to flatten the thread. Ultra thread gets a near floss-like quality when you do this. Then, with the dubbing needle, split the thread and insert the index finger of your left hand between the two strands. Put that little clump of rabbit fur dubbing between the two strands and pull your index finger free. Then place that finger against the thread and give your bobbin a healthy clockwise spin. This will cord up the thread and trap the dubbing between the strands. You should be left with a short, rather bushy dubbing noodle. Wrap the noodle around the hook shank preening the fur rearward as you go. You should end up with something that looks about like this.
For the soft hackle, you can use regular Hungarian Partridge, like on the left, but I really like the look of the skin on the right that's been dyed ginger. Pull out a single feather with fairly short fibers. Strip the fuzzies off and then, while holding the tip, pull the majority of the fibers downward. These'll be used on the fly. Snip the tip off, leaving a small triangle for a tie-in anchor. Give your thread a counter-clockwise spin and then place that little triangle just behind the hook eye. The counter-clockwise spin will help the thread to loop slightly rearward and get hold of the triangular tip. Continue taking wraps to ensure the partridge feather won't pull free when you go to wrap it. Grab the stem with your hackle pliers and begin taking wraps forward toward the eye pulling the fibers rearward as you go. One or two complete wraps is all you need. When you get to the eye, secure the stem with a few good wraps of tying thread. You can then reach in with fine-tipped tying scissors and cut the stem off close.
Take a few more wraps of tying thread to form a nice, neat head and then secure the thread with a 4 or 5 turn whip finish. Finally, snip or cut your tying thread free.
Although there's no wrong way to fish this fly, when trout are rising to take naturals from the surface, I'll fish them just as I would a dry fly. They float well and are surprisingly visible for such a small pattern.
A few rapid false casts usually dries them out but if they get very wet and start sinking, try blotting them with an amadou patch or similar to remove water from the fly. Then brush a dry floatant or desiccant into the rabbit fur and blow off the excess and your fly should be riding high once again. This little number has really saved me on multiple occasions during the sulphur hatch when the trout are refusing everything else.