There is mounting research showing that stress can be a contributor to a wide cross section of diseases. When we think about preventive medicine, we often think about foods or chemicals that will prevent disease. But stress is a physical reaction that is a precursor to many diseases itself.
Modern society is full of sources of stress. There is no end to it. The best thing you can do is learn how to manage that stress.
You probably already know how to manage your stress, without realizing it. Some things make you relaxed, somethings freak you out. Stick with the former and avoid the latter.
If you're looking for more idea, here is a site that has 101 ways to cope with stress. Some of the suggestions they have are
Avoid tight fitting clothes.
Simplify meal times.
Teach a kid to fly a kite.
Take a bubble bath.
Vent to someone.
