Inhale, exhale. You do it 24-7, usually without noticing it at all. Take a moment to tune in to your breathing. It's an easy, do-it-anywhere way to soothe your body and mind.
Take a slow, deep breath, filling your lungs with air. Then let it out slowly and fully, feeling your muscles loosen up as you do. Take several deep breaths whenever you feel stressed out. Deep breathing not only relaxes your mind, it also sends more blood flowing through your body.