Normally the one thing that calms an Aries is letting them fume and get all of their anger and energy out. But sometimes they find people in life that know how to calm, sooth, and keep them in check.
Leo finds calmness in creativity and physical activity. This is a person who feels calm after getting done with a project or after a good workout.
Sagittarius finds calmness when they finally have alone time to think and work stuff out. Usually a long drive by themselves or taking a walk clears their mind.