Relax all of your muscles, including those in your face and jaw.
Begin breathing in deeply through your nose, focusing first on expanding your body outward in 360 degrees for the first 2/3 of the breath and then upward for the last 1/3 of it.
When you feel like you can't take in any more air, take in some more and hold it for up to 5 seconds. Focus your breath on tight areas.
Slowly let the breath release through your mouth.