A technique I have used to make my breathing pattern (in through mouth, out through both nose and mouth, but mostly nose) consistent is to practice it while resting between laps or drills. I will take a breath above water, then dip under up to my goggles and exhale through my nose and mouth. After a while doing this, it had become second nature. Muscle memory if you will. I basically modified the yoga breath rest concept to help with my breath mechanics. I feel it is a good way to take advantage of the time spent between drills/laps.
Obviously this doesn't do much for integrating the breathing in whole stroke, but does help for the mechanics of the breathing by itself.
Hope this helps,