One of my favorite things to do is to fish high altitude lakes using a float tube.  A few years ago I fished several lakes above Tioga pass and have had so much fun hooking good sized brook trout.  The thing I noticed the most about these small lakes is that I was always trying to find out where's the fish.  I've learned that through much trial and error that good size trout behave just like fish in an aquarium.  But, for the most part they stay in the center.  I've had more luck starting in the center of a small lake with a matuka or something that resembles a minnow using a sinking line or unsing a leaded line  If you have any more tips for flyfishing let me know.