I fish most of the time subsurface. Start out shallow in the water column and the slowly go deeper. Also vary the retrieve until the fish tell you what they want.
I also carry two rods, one with a white or yellow and the other with a black fly on it. If these don't work, I go to a shiny fly, a brown fly, orange, olive, brown and then purple.
I also start with short casts and then increase the distance, so I don't spook fish.
Hope this helps you.
Rick