Other times, the hatch is so prolific that your fly is lost among the thousands of naturals on the water. You can solve this problem by tying on something that does not attempt to match the hatch, but that looks edible and familiar nonetheless. Terrestrial patterns often work. Sometimes a big Woolly Bugger dragged past the nose of a mayfly-sipping trout will bring a violent strike. Don't be afraid to change flies.
Most fishermen believe that the shape and size of a fly are more important than the color.
But you can give yourself an edge by matching the insect's color, too. Try a nymph anytime. Even after trout have clearly begun to eat insects off the surface, they usually continue to feed on nymphs. Furthermore, they are somewhat less selective and wary when feeding subsurface than when they must expose themselves to pick an insect off the top of the water. For these reasons, try fishing a nymph just an inch or so under the surface through the entire cycle of a hatch.