Here are some simple tips on adding tails and leggs to dry flies that look great and work well. This example is a size 18 BWO using clear tubing colored with a green marking pen.To accomplish this follow the steps here:
1. Wrap the hook shank with thread ( In this case I'm using 3/0 thread and a size 12 - 4x long hook so you can see the process)
2. Add the heat shrink taking enough wraps around the hook shank and the heat shrink to reach the point where you would like the 1st leg.3. Add the tail. In this case I used a heavy monofiliment in a brown color so you can see the process. Normally, I would use 6# or 8# monofiliment in a color to match the natural insect.
4. Use the soidering iron to shrink the tubing and seal the tail with Zap-A-Gap (Thick super glue). I use Zip Kicker, a super glue accelerator the set the tail and seal the tube quickly. This also holds the tube in place on the hook shank.
5. Add the 1st leg, between the tubing and the wrapped hook shank and anchor with the thread, taking sufficent wraps over the tube and shank to reach the next leg location.
6. Anchor the second leg in place as with the first and continue wrapping shank toward the eye.
7. Add the wing post. (Note: White tubing will increase visiability vs. the clear I used here) Use the soidering iron to seal the post and hook shank tubing with the thread. Crimp the post after heating the tubing with pliers to seal the air Bubble. 
8. Add the wing (in this case parachute style) using a saddle feather to match the natural insect. 9. After tying off the thread seal along the hook shank with super glue or head cement.
