Gotu Kola and Licorice root are the best ones to start with. There are other more refined compounds you can buy from health practitioners, but usually these two are all you need and the more refined products are refined from licorice anyway for the most part.
Avoiding refined Sugar and caffeine (even the good caffeine in green tea should be limited) and other stimulants is very important. Meditation and a good night's sleep with regular hours is very helpful.