With the trough or pocket of air by your head you don't have to lift your head up to breathe. To breathe into the trough you just have to rotate your head a little without lifting it. If you try and lift your head you disturb the bow wave, reducing the trough. Also, when lifting your head you tend to breathe too far forwards - and try and breathing over the high front of the bow wave.
Take control of your swimming technique using this simple but super-effective tool. Set your desired stroke rate and swim to the beep. Will you set a PB on the very first swim?