Film School Rejects have (has? I think it's "has") a series of articles called 6 Filmmaking Tips From..., and last week it was Charlie's turn. The 6 tips are drawn from various interviews Charlie has given over the years, and there're links to those interviews within the Film School article.

Being eccentric won’t make you as strong a writer or director as Kaufman, but the two truly obvious things about his work ethic might help.

One, he takes his time. His scripts take years to develop, meaning he doesn’t steamroll through them on a tear. He’s calculated and calculating, taking great care in handling difficult concepts and experimental structures. This may not be universal, but chances are if you’ve got something that laughs at convention while exploring huge ideas and you haven’t spent more than a year on it, you’re probably still selling your story short.

Two, he knows an unbelievable amount. Just reading through interviews and speeches, it becomes clear that he’s insanely well-read, swirling a large amount of facts and ideas and perspectives around in his brain. That probably helps when attempting to plumb the depths of the human experience, but being able to channel those thoughts into a clear purpose (even if the film you’re making is ultimately open to interpretation) is vital. (Source)

Additional information