For perch and crappie I like any small jig or spoon tipped with maggots or waxworms. Pieces of nightcrawler work well too. The smallest jigging rap, tipped with a tiny piece of one of these is great too.
For specifics, I like shrimpos, ratsos, demons, stingers, nuclear ants, swedish pimples, genz worms, frostees, frostee jigging spoons, or fatboys. Tip all with maggie or waxy and just gently jig them. Perch are generally bottom oriented and crappie tend to suspend at least 5 or so feet above the bottom.
Tyler