To fish a worm fly, start by attaching it to your fishing line with a loop knot. Cast the fly close to the desired spot and let it sink for a few seconds. Then, retrieve it by gently twitching the fly rod as you reel in the line. This motion mimics the movement of a real worm, attracting nearby fish. Vary the speed and depth of your retrieve to imitate different worm behaviors. Observing the water, look for signs of fish and the best areas to fish. Experiment with different colors and sizes of worm flies to determine which ones are most effective. Remember to use a lightweight fly rod and a fine line to achieve a natural presentation. Keep practicing and adjusting your technique until you find the right rhythm for attracting fish with a worm fly.