Love those Smallies
I totally agree with KY, Murray's book is excellent. Check out Murray's Hellgrammite and the James Woods Bucktail. Both effective and easy to tie.
Tarheel is right on track about the crayfish, especially later in the season. Use small versions early - like Jim's Lil Bugger. Gummy Minnows, or as I like to call them - "The Expensive Fly" are also a good choice.
Try this - 2X nymph hook in size 4,6,or 8. Add bead chain eyes near the eye on top of the shaft. At the bend, add some rabbit (or other soft fur, even maribou) to make a tail about half the length of the hook. Then wrap chenille halfway up the shaft and then wrap a second color, that matches the tail, to the beads. Turn the hook over and add a few strands of a flash material long enough to cover the hook point. Colors I have had success with are Yellow/White/Yellow, Yellow/Chartreuse/Yellow, and Blue/Black/Blue. Fish it like you would a Clouser. This was taught to me by Jim of Jim's Lil Bugger. He calls it his spinnerbait fly. Oh yeah, don't tell anyone about it. Shhhhhh.
To Miss Nancy - she hated fishing, but loved a fisherman.