You might try trolling streamer flies. Patterns that imitate leeches and minnows have been very productive for me so far this year, now that the water is approaching 60 degrees. The Thin-Mint Leech, a mottled marabou leech (wine-red, brown, olive and black marabou feathers), and the Woolly Bugger are the leech patterns that I've used. The minnow patterns I've used were my own creations; however, you can buy a Royal Coachman, Mickey Finn, or a Muddler Minnow at any fly shop or practically any store that features fishing tackle. If you twitch the fly into a start and stop motion as you troll slowly, it will imitate the action of a crippled minnow. I actually saw the wake of a trout intercepting one of my minnow patterns as I was twitching it along. It was soooo cooool!