"Negative emotions do not exist in any object or situation. They are purely constructions of thought. Whenever you are angry or afraid, you have done it to yourself, driven by the more primitive parts of your brain"
So I feel the best thing to eliminate stress is meditation. Meditation is just learning to keep your mind empty from invading thoughts that trigger negative emotions.
It hard to learn this, most people give up because they don't get noticable result quick enough. But I can assure you that if you keep with it, and start with only small periods of mediation a day( 5 mins) and gradually increase it, you will succeed.
I recommend buying a book on how to mediate.