I find it somewhat entertaining that there are all sorts of methods and procedures for precisely how to breathe. Sure, there is the one rule ("Don't hold your breath."), and there are the two guidelines ("Deep, not shallow." and "Slow, not fast."), but there really *isn't* a procedure for precisely how to breathe on a real-life dive.
It's not evading the question to say that it's really more of feeling it and going with the flow. I can certainly tell when my breathing is elevated, as I'm sure most attentive divers would also say. At the same time, there isn't any particular regimen I use when breathing underwater. Even if I were to try some counting method or what have you, it would break down all the time, since breathing is my primary method of buoyancy control.
While I do not discount the idea that strict regimens of breathing can help some divers, for others, trying to follow a count simply adds another element of task loading while impeding the proper use of breathing for buoyancy tweaks. For those divers, it should be perfectly adequate to simply "concentrate" on being calm and relaxed, with the occasional thought toward breathing deeply.
If you come up with CO2-induced headaches from shallow breathing, by all means try one of the counting regimens to consciously force yourself to breathe more fully. If you've never had a headache and you're just wanting to do breathe the "right way", don't get yourself all stressed and task-loaded by trying to figure it out -- you're doing fine as it is, so just relax and enjoy yourself.
(I've never tried to adjust my breathing underwater. Diving is so relaxing, I'm naturally breathing slowly and fully. It never occurred to me to consider how I was breathing until I was showing my sister's family some dive home video I shot. They asked me, "Do you really breathe that slowly?" and obviously, the answer was "Apparently.")