Brian, there are many fly patterns that will work well for warmwater species. The others have given you some great advise.
I use some flies that are generally designed for Steelhead, or Alaska type fishing, such as the MOAL & Intruder style flies. Stream Smallmouths particularly like these.
Here's what I go with for the types you mentioned.
- Bonefish or flats types of flies: Gotcha's, Crazy Charlies, Squimps - these are simple, imitate shrimp, but work well as crayfish too. I adjust the colors to imitate the local crays, which are mostly rusty brown to olive green shades. Some have blue, red, purple or orange hi-lites too.
In the past, I tried to imitate crayfish with patterns that had double claws & all the details you see on the real thing & on many cray patterns, but found all that was not necessary. Now, I much prefer the simple, impressionistic patterns, and the fish like them too. I also like the fact that the simple patterns take less materials & less time to tie, and since I end up losing quite a few, it's not a big hit on the wallet.
clouser minnow pattern
Use a lot of these in all kinds of sizes. If you tie them very small, like size 8 or 10, go with finer textured hair, like Arctic or Red Fox. Bucktail is the standard material, but when you go small, the finer hair works better. Keep them sparse too.
some kind of leech pattern
I like anything with rabbit strips, but also like a Clouser style fly tied with black ostrich herl and some flash, like copper or bronze, or both. Ostrich herl in other colors too can be used as I mentioned above for the smaller sizes of Clouser Minnows. I like ostrich better than marabou for some tying as marabou will sometimes mat up, especially if the water has a lot of suspended particulate matter in it. That's not usually a problem during the colder months, but can be when it's warmer.
- Again, rabbit strip flies work well. I tie them in many colors, but like to think in terms of what works well with jigs or other bass lures. Black & blue is a great jig color combo & it works well with flies too.
I'll add some weight to these, usually a conehead, bead head or barbell eyes.
- Can't go wrong with poppers. Deerhair bugs work well too. I also like some of the foam flies that are tied for the big western trout rivers, like BLT's, Triple Deckers, or Chernobyl's. All of these float well and can imitate many things, including hoppers & crickets, big adult Stoneflies or even Damsels & Dragonflies.
I recently posted some spinner flies I had tied up. I also still fish with spinning & baitcasting tackle, and have no qualms about using a little hardware with my fly rod especially for panfish. The flies I posted are very simple, and I've added some clip on, inline spinners to them. They work quite well, and can be easily cast with a 5 wt. In smaller sizes, they could probably be cast with the 3 wt. May not be something all folks would do, but since your in NH, you probably have a good number of White or Yellow Perch up there too, and these spinner flies can be deadly on them. Crappies like them also!
Here's the link to that post: Some recent tying!
Hope this helps!