What are some relaxation techniques I can use when surrounded by a stressful environment?

Stay active. Exercise is a great way to relieve stress. Your body releases endorphins during exercise, which can help you feel calm. If you exercise 30 - 60 minutes a day, your stress levels can improve. When stressed, take 5 slow, deep breaths with your eyes closed, then roll your shoulders forward 5 times, then back 5 times. This will slow your heart rate and release tension in your neck and shoulders.
Meditation. There are many ways in which to relieve stress. Meditation is an important and effective way to do this. A simple meditation technique: find a quiet, comfortable place where you can be undisturbed. Close your eyes and take slow deep breaths inhaling through your nose and exhaling through your mouth, "hyper-focusing" on listening to your breaths. Do this for 5-20 minutes daily.