A good starting point....
A good place to start would be a pheasant tail nymph, then graduate to a hare's ear nymph. These two flies are fairly easy to make, and only use a few materials, yet will teach you a lot of "basics". Start fairly large - 8s or 10s. Then work your way up to size 16s. By the way, USE your first efforts. They are usually better flies for catching fish than the more "professional" looking flies we make as we get experienced!