Some helpful hints after making several thousand poppers:
http://www.flytyingforum.com/pattern6910.html
(1) look at the pattern at the site shown above
(2) note that MAJOR improvements have been made in the technique since then, but the basics are the same. What follows are some of those improvements.
(3) use a heated bobbin to create a hole in your foam head to insert the hook. Depending on the size of the hook eye, you may have to wiggle the bobbin a little while it is in the foam to create a bigger hole
(4) Using a large eyed sewing needle (canvas needle) insert the legs through the head at the level of the hole you created with the bobbin. The advantage here is when you use CA glue to put the head on the hook you will also be glueing the legs in place from the inside.
(5) I've got a couple of articles on this site about superglueing foam you might want to look at.
(6) Always use a long shank hook. The thickness of the foam can substantially reduce the hook gap once you have assembled the fly, especially if the foam is near the hook point.
(7) The order of addition of materials to the hook should be: mono for weed guard (if you want to have one) then other tail materials.
( Make sure you have a base of thread on the hook shank before glueing the head on. I use almost exclusively flat waxed nylon.
(9) 3D eyes or something Michael's carries (on occasion) called Botique Fleur black mini round gems work better for eyes than stick on tinsel eyes
(10) Make sure legs are not so long that they will get crossed with the bend of the hook. Rubber legs are very fond of doing this.
(11) Rubber and silicone legs act entirely differently in the water and give a popper a very different action.
(12) "Fine" rubber legs (usually get mine from jannsnetcraft.com) are excellent for small poppers and hoppers etc.
If you have any questons, just PM me and I probably have an answer, although maybe not the one you want.