“Generalizations are no use — give one specific thing and let the action say it…
“When you have people talking, you have a scene. You must interrupt with explanatory paragraphs but shorten them as much as you can. Dialogue is action…
“You tend to explain too much. You must explain, but your tendency is to distrust your own narrative and dialogue…
“You need only to intensify throughout what actually is there — and I think you would naturally do this in revision, anyhow. It is largely a matter of compression, and not so much of that really…
“You can’t know a book until you come to the end of it, and then all the rest must be modified to fit that…”
This advice came from Perkins’ letter to Marcia Davenport, as quoted in A. Scott Berg’s Max Perkins: Editor of Genius, which I finished reading last night (overall I thought the book was a bit uneven, but it made for fascinating reading, especially the parts about Thomas Wolfe, who I knew next to nothing about).