A break fall is nothing more than an advanced way of rolling. If uke focuses on the forward roll the break fall takes care of itself. In other words, if a student can do a splendid forward roll he/she should be able to do a splendid breakfall.
Lyle, I would disagree in the sense of the body's landing position. A person could have splendid forward rolls but always roll up to kneeling or to standing.
To me the single most important thing of a breakfall, whether one arrives at it via a fall from a height, via jumping forward over one's arm, or via going straight back/down with legs flying up in front of one's body, is having practiced via sheer repetition the proper landing position.