Breathe gently in and out and purse your lips when breathing out
If possible, breathe in through your nose and out through your mouth in a steady slow rhythm. Try to keep your mouth closed when you breathe in through your nose. As you breathe out, pucker or 'purse' you lips (as if you are about to whistle). This interferes very slightly with the air flowing out. Try to make your breath out twice as long as your breath in. This helps to empty your lungs of old air, and to make as much room in your lungs for fresh air. To do this you may find it helpful to count 'one, two' as you breathe in, and 'one, two, three, four' as you breathe out. Do not hold your breath between breathing in and out.