stress can be relieved by not thinking about that matter and take your mind on other things because continuous thinking about the worried matter is not of worth.
Obviously letting mind rest is best way to relieve. But it is not easy to do so. Hence, there are remedies like Yoga. I feel best way is to play with small child when you feel stress. Child is nearest to nature and is least worried. So, company with small child will enable you to relieve your mind.