Meditate.

Meditation is a way to calm both your body and your
mind—it helps you slow down, clear your mind of
clutter, and feel calm. Take a few minutes and try this
simple meditation exercise:
Sit in a comfortable position in a quiet room, either
on a chair or cross-legged on the floor. Close your
eyes. Focus your attention on a silent thought, word,
or phrase. If your attention wanders, gently redirect it
back. Concentrate on the sensation of each breath as
you inhale and exhale.