The only adequate answer is "it was his day" and things came together.
And the obvious corollaries are that he trained very hard, is in great shape, and has a great coach.
Besides that, there is no "secret". It is not his spirituality, but I am sure it didn't hurt. It is not his amazing running economy alone, though that did not hurt either. And it's not just his coach -- who may very well be a great match for him. It is not just his graceful form, either. The altitude surely helped in some way too, but it did not make Ryan Hall great alone. Nor is it any one element in his training.
It is all of these things coming together at the right time to produce a great race. It worked for him.
Let us laud Ryan for his excellent race without trying to pick apart his life, training, coaching, and belief system to find out what works. This is missing the point.
If any runner were to go as fast as Ryan, one could pick out things in their life that "look different", but never are they the secret to why they ran so well. Nor will copying everything Ryan Hall does make every other runner as fast as him. Something within Ryan shone through today: greatness. But there is no "secret" in that greatness, just hard work and having the right day -- and it's a mistake to think otherwise.
Training is important, but, it's like an old saying: there's twenty ways to sing tribal lays and they are all right. At least some of the time. Today, Ryan Hall's way of singing was shone to be "right", and his results are hard to argue with. But there are other "right" ways of singing.
Just a thought to, perhaps, temper some of the thoughts that immediately get thrown around any time someone performs well.