Stress falls on a continuum, with distress at one end and eustress at the other. Distress is the anxiety that can immobilize us. Eustress, by contrast, is associated with happy or anticipated events that have some degree of stress associated with them. Someone facing an unexpected eviction notice experiences distress. Someone about to perform in the Olympics has more eustress than distress. More than 80% of all illnesses are linked to stress so it's important we learn to cope with it.
Here's one simple but extremely effective method of dealing with it:
At the beginning of every work day, place a bowl with 20 nickels in front of you. (You can do this even if you work at or from home, too.) As stress arises or arrives, decide for each incident how much of your 20-coin allotment you are willing to give that incident. If it's a big stressor (criticism from your boss), you might allow the expenditure of 5 whole coins, knowing of course that you have the rest of the day to get through. If you end the day with leftover coins, you can congratulate yourself for keeping stress under control.
There are many other things you can do, but the operative word here is "do." All the knowledge in the word is meaningless if you refuse to apply it. One application you can make is the K-I-N-D method of dealing with conflict.
K = Kind
I = Informed
N = New
D = Definite
The technique involves your requesting a meeting with the difficult person who is causing stress. Start off with kind words, words that encourage cooperation. Next, demonstrate that you have taken the time to learn more about the person, what is important to him or her, what he or she prefers in terms of work. The third step requires you to do something novel, something you've not tried before. Finally, do not permit the exchange to conclude until you have made a definite overture to ensure future success. What can you promise the other person you will do differently? What are you asking him or her to do differently? Set a time to meet again and review your individual attempts to achieve collective improvement.
You are the "controller" when it comes to stress. Take small steps on a habitual basis. Learn to make stress work for you, not against you.