A four or five weight with a floating line is a useful starting outfit in a small stream. Carry a foam ant, beetle or small terrestrial pattern and a compact nymph or streamer for fish that will not rise. Keep the leader manageable in the confined casting space.
Begin with a quiet landing and a natural drift. Feed enough slack to prevent the current pulling the fly sideways, but stay ready to set the hook. If a fish follows without eating, try a small twitch and another pause. There is no need to make the fly race through the entire pool.
Fish below the surface when the upper layer gives you no response. A small sinking fly can be guided beside a boulder or through the slower edge of the inflow. Work the pool thoroughly without standing where the next cast should land.