Breath

Get this book and learn the techniques. Exercise, good food, proper sleep, right medications etc, all these are fantastic but the missing piece is breath work. Regular breath work can ridiculously reduce stress and a long list of the problematic things including chronic problems. You can't go wrong here, the only demand is time.

The Healing Power of the Breath: Simple Techniques to Reduce Stress and Anxiety, Enhance Concentration, and Balance Your Emotions by Richard P. Brown and Patricia L. Gerbarg