Years ago while teaching eighth-grade language arts, I would collect 80 multi-page papers on Friday. I had a formula: assign a piece of writing on Monday, struggle through superficial conferences all week, and collect rough drafts on Friday for a completion grade. The following week I would ask students to revise (without instruction). I collected final drafts on Friday and wrote lavish comments on them in sparkling green ink.
These days I let the students set their own schedules—writing comes in when they decide, and I spend the bulk of my time on rough drafts, doing everything from complimenting good word choice to asking about the “so what.” I model revision. By the time a final draft comes in, I know the writing well from having experienced all of its incarnations. My penciled comments at this point are brief and address the full life of the piece.