I think the part I liked the most from this interview was where he gave the two rules for life he has: 1. never lie, 2. date every piece of paper he writes anything on, for posterity.
There's a neat 10 minute fragment of an interview with him on youtube [1], about the notebook he made prior to filming The Godfather. He took the paperback copy of the novel, which he'd annotated, cut the pages out and pasted them onto larger pieces of paper so he'd have more margin to annotate in, and put the whole product in a huge three-ringed binder that he relied on more than the script itself when filming.