Yep, #1 has to be presentation. You can be dead on in size, shape & color and the fish won't touch it if it's dragging across the water or the direction from which you cast is up where the fish see motion or fly line. So I guess it's presentation from the right possition? My eyes aren't good enought to tie on anything smaller than size 20 and those can be tuff. I mostly use Adams or BWO parachutes in those situations. If I get the drift right, I usually do pretty well.