There are techniques which consciously control the breath. We won’t talk about those here. Instead we’ll talk about general principles.
Principle 1: Your stomach muscles control your breathing. Relax your stomach and air comes in; contract your stomach and air goes out. Sometimes this is called belly breathing.
Principle 2: The inbreath is shorter than the outbreath. The outbreath should be about twice as long as the inbreath. A common suggested ratio is three counts for the inbreath and 7 counts for the outbreath, but you don’t have to be too strict about this.
Principle 3: Mouth closed.
Principle 4: Slow down. Actually, this will happen naturally. Keep your energy in your belly (technically your tiantien) and your breath will naturally find its appropriate pace.
Principle 5. Don’t hold your breath. Breathe in. Breathe out. Repeat. Repeat again…