Maslow's hierarchy things help: Sleep (where possible), diet, water, exercise (HIIT cardio and weightlifting), get outside, routine, defuse catastrophizing thoughts with reality, and not everything is as hard as it may seem (no mind, grasshoppa).
Avoid: alcohol, walnuts, almonds, soy, licorice root (black licorice candy), mint, certain oils (canola, corn, cottonseed, soybean, flaxseed, sunflower, safflower, palm kernel, "vegetable"), sugar/HFCS, carbs, trans-fats, and excessive omega-3.