flys range in many colors and sizes, and are unique to different types of areas. The best advice i would think of, would be to go to a local fly/fishing shop. Ask them what they would recommend for your area. For fly fishing in itself, it really depends upon approach or apperance. You've gotta put the right fly in the right area. Maybe buy a book, or rent a video on fly fishing, or just go out and watch some experienced fly-fisher men, and pay attention to how and where they present their fly.

Good luck!
Idaho