Here's a simple relaxation technique:
Deep breathing is a simple stress reliever. Find a quiet moment to yourself (or make one) and sit comfortably or lie flat on your back. Close your eyes. Inhale slowly and deeply through your nose. Each complete breath (inhale and exhale) should last at least 5 seconds. Feel the air expanding your chest and diaphragm. And feel how your body reacts. Your muscles will start to relax automatically, and the tension will melt away. Try to quiet your mind as much as possible, but don't beat yourself up if you can't. Consciously relax each muscle in your body, starting with your feet and legs, then your abdomen and back, then chest, arms and neck, and finally release all the tension that is stored in the muscles in your face. Do this slowly and thoroughly, which usually takes at least 10-20 minutes.