A recent issue of the New Yorker (the same issue that published David's poem "It Could Happen to You") included an article about the poetry of A. R. Ammons. The article mentions Ammons' Paris Review interview, which David conducted in 1996. You can read the interview here.
Even better, you can listen to the complete interview tapes. These are a treat; as one would expect, Ammons' discussion of how he works is fascinating and filled with terrific advice for all poets, regardless of where they are in their career.
(I almost stopped reading the New Yorker piece early on, when the author describes Ammons as "puttering." Clearly he never met this great genius--which I did, in Ithaca, on many occasions--or "puttering' would never have come to mind. sdl)