Braking from speed I use both brakes but almost all the work is done by the front. My front brake pads don't last anywhere near as long as the rear. Sometimes though I use just the back brake, very slow speeds or loosing a little bit of speed into a corner in the wet. I don't do it consciously it's just something I've noticed. Braking into a fast corner is something I often do when it's dry then accelerate out, it's all good fun but going out for a ride on some very twisty roads, making best progress but trying not to use the brakes at all except when coming to a stand still makes a good ride too.
Braking is something you can read about then mimic but there is nothing like real time practice. Most of my practice was done growing up on pedal bikes, I would spend hours on the beach at Seaforth (Liverpool) when the tide had just gone out and the sand was hard. I was amazed as to what my mate and me could do on or bikes. We could have put on a show with our skidding tricks, sadly the day's before camera phones.
I think that practice has helped me through into motorcycling. I'm not saying that I have never got it wrong and lay my motorbike down though, that was a learning curve but another boring story, sorry. Anyway, it's 2:15pm, the sun has just come out and I'm not even in my bike kit yet, got to go.
