
Here is the fly just before cutting for the head. While I may have put a dab of cement on the horns or cheeks at the tie-in point (in order to stabilize what will be cemented later anyway when I cut the stems), I HAVE NOT gotten any cement on the materials forward of the wraps of thread. This is because If everything is stiff from cement before cutting and shaping the head, it is difficult to compress or get smooth wraps an hard, jagged edges. If everything is un-cemented them it will compress a little after cutting and give you a better shape. I tie everything in before cutting, except sometimes topping and horns. On a fly with no topping always everything first.

Here is the head after trimming. I cut the stems with scissors, and then use a scalpel to cut the wing fibres. You can get a scalpel and 10 blades dirt cheap online, and I highly reccommend it. It is sharper than a razor blade, and the handle turns it into an easily manipulated tool. I cut on an angle on purpose - this gives me a slope to put the thread. If you cut straight down you will be in a pickle. Remember it is easy to cut more but once it is cut you can't go back, so less steep is better at first, until you have practiced a bit. A sharp blade makes it easy to "carve" the shape you want all around, so to speak, without messing up the fly behind. Of course, when cutting, the wing and materials secured at the head tie-in point are secured in a firm pinch with the other hand. I have found that using a scalpel or razor causes the wing to move around less than using scissors, but that is just me.

Here is the head after wrapping thread. I do not wrap straight forward and back, as you can see there are all kinds of angles to the thread to keep it from slipping down the slope. Of course, good wax is a must - you can see it on the thread. I flatten the thread and try to get everything covered - a few little gaps are ok if you use black varnish for one of your coates, but I try not to have any gaps. Flat thread, lots of wax and the minimum number of wraps, then a couple of whip finishes and cut. Also, once you have wrapped and cut, if you have a lot of wax on your thread it will have built up at the head and you can catually "mold" the shape of the head to a degree with your fingers or the handle of the bodking to smooth everything out and make sure the shape ios consistent. This will only smooth out, not change the shape you already have. In any case, monkey with it as little as possible because if you get too rough or try to do to much you can push the whole thing out of kilter.

Here is the finished head. Note that the shape of the head is from the shape of the head, so to speak. It is hard to make it look good with cement if it doesn't look good beforehand. I will use one coat of thin cement to penetrate everything, and then two or three coats of thick varnish and call it a day. If you are going to put a fly in a fram it is a good idea to let the varnish cure completely (24 hours) and then look at it again, because the varnish will contract a little as it dries and may give a funny shape when it is fully dries, in which case one last coat will help. I try to use as little as possible on my thick coats, just a drop on the end of a bodkin as I rotate the fly around and apply it to the head. I have the vise angled up at about a 30 degree angle when I apply the varnish, which keeps it from running down the slope and into the eye (or I feel like it does). Too much varnish in one coat will seep around the head before it dries and leave a blob underneath the head that throws off the shape.
And there you have it. Hope this helps someone!
-Jeff