If you are trying to match the hatch this may help. In many areas we will experience Grannom Caddis and Hendrickson Mayflys. My area in South central Pa is starting to see them as I speak. If new to fly fishing try a dark color size 14 wet fly. Just cast down stream and let it swing a inch or so under the surface. Best time to fish this way is when you see some flys emerging and a fish or two rising. If lake fishing do not be afraid to try the wet flys also. Jut cast wait a few seconds and start a slow retrieve. I usually put a small shot about a foot in front of the fly. When I say small I mean shots designed for fly fishing not the reopenable type. This will help cut the surface film and let the fly sink up on impact. Crappie and other pan fish eat these insects as well as Trout. Theaddictedangler.com School of angling