Relaxation training also is an effective strategy. Usually we use progressive muscle relaxation or suggestive guided relaxation.
For both exercises, find a place where you are unlikely to be disturbed, switch of your cell phone and wear comfortable, loose clothing.

Please use the links below:

Try to practice every day. Choose a moment that is not stressfull, the more you stress you experience, the more difficult it will be to succesfully train your ability to relax.