There can be lots of reasons why the guy next to you is outfishing you by a lot. I would put them in this order:Presentation
(Depth, retrieve). Usually, but not always fishing chironomids 1-2 ft off the bottom works best. Vary your depth or fish naked sinking line in deeper water so you can fish the entire water column. Don't fish below the thermocline.Fly size
For chironomids generally fish one size larger than what is hatching - size 12-16 are common. Unforutnately Roche fish that I throat pump often contain 3 or more different sizes so
. Leeches and damsels I generally fish small (micro or smaller) with a fast retrieve. Location
Roche has definite "highways" that fish use to travel between deep water and shoals and I've had a lot of success fishing these. If you are 10 feet off the highway you may not catch anything. Later in the year you can generally spot these as grooves in the weed cover. Fly Colour
Colour can often make the difference between a good day and a great day. black, brown, green, ASB, wine, chromie for chironomids. I personally never start with black with red rib. I have found the poor water clarity in Roche means white or copper beads work better.