When swimming freestyle, breathe into the trough with your mouth and exhale strongly into the water through the nose. In between breaths, hold your head in one position. Only turn your head when breathing.
While swimming freestyle, create a bow wave with your head and body to form a trough on either side of your head. Rotate your head a little and then breathe into this trough. To avoid over-rotating, keep one eye above the water and the other below. Increase the rate of exhalation as your body slides forward and the head rotates. Breathe on both sides to maintain symmetrical strokes.