Understanding by Design (or UbD) is one of our core pillars at egghead.
It's an approach to designing learning experiences that begin with the end in mind. You start with the goals of what you want someone else to learn, and backwards plan from that point.
This seems obvious when you say it, but when most of us go to teach something, we look at the big pile of material we could teach – all the tips and principles and techniques we have at hand – and organise them into little related clusters and try to stumble towards some vague end learning goal.
This is forwards planning. It seems logical. Except if we don't pick our destination ahead of time, it's just wandering around without a path. Hoping we end up somewhere nice by chance.