When you apply the front, the entire weight of you and the bike are pushing against the brake making it efficient. When you stomp the back, that same weight simply drags the back tire along.
Using the front brake has to be an unconscious thing.
Find yourself a large parking lot and practice as much as you can. Practice stopping in a straight line, not in a curve. In a curve, stand the bike up to go straight to do a panic stop. Learn, read, ask as much as you can but you've got to get out and practice. You're going to have to un-learn that foot thing! Practice!
