First, break the clenching cycle by consciously recognizing you are clenching. Stretch your jaw by opening wide or moving laterally. You may even want to rub your jaw joints. Next, relax your jaw and gently place your tongue behind your upper front teeth. Let your tongue relax--don't push on your teeth. You will notice that you can't close your teeth in this position--that's the point. Make this your new tongue resting position. Repeat this exercise as needed.