Paint some furniture, knit a sweater, draw a picture, do woodwork. Engage your mind in pursuits other than worry.
Pick up a book and read for pleasure. It is a great way to lose yourself in the imaginary world of another person.
Look at the beauty around you. Breathe in the air, feel the wind on your cheeks. Engage all of your senses.
This is the primary way to reduce stress. Spend time with the God of the universe. He wants a relationship with you.