The optimal way to reduce stress is to change the circumstances that are causing it. You can also improve and strengthen your ways of coping, beginning by getting lots of sleep and good nutrition. Turn to friends or even a therapist to have a secure place to unload things that are troubling you. Get some good, perhaps aggressive, exercise.
Find things that you enjoy doing that make you feel good. Some examples are running, cooking, and yoga. Make short-term goals for yourself, such as loosing 2 pounds in one week, and work towards that goal.
Remember that some stress is a natural part of living. The key to handling excessive stress is including enjoyable activities as a regular part of your everyday life.