Good braking technique comes with experience. I favor the front brake most of the time unless I have questions about the traction. For instance on wet paved downhills, I might favor the rear more than usual. Lose that front end in a skid and you can go down in a heart beat. Skidding in the rear can be be compensated for with body shifting. I very rarely use both brakes at the same time. The one thing I try to do is not use my brakes. They are the last resort. Nobody taught me to do this, I just sort of figured it out over the years.

I do not pretend to be an expert. I will still occaisionally get myself into trouble with poor brake usage. Usually on some trail where I miscalculate the trail conditions. Hence the no brake policy whenever possible. A good way to learn braking is to ride on ice.