When fishing dries to regular risers try to match the size, colour and profile of the natural as your first line of attack.

 

If this fails to work always go down in size and very often this will bring an offer, it’s easy to misjudge the size of a natural and they are very “delicate” when compared to our crude imitations.  Sometimes a bigger imitation than the natural insect will work although not very often, remember there are no absolute rules!