By this point in the semester my students have had at least one if not two papers on which I have commented extensively, including comments on clarity, grace and style. Together we have begun to locate particular patterns in their writing to focus on for revision and future papers. From this point onwards, then, I select only one paragraph per paper to mark for style, grace, and other formal matters. As a matter of discipline I allow myself only three more comments on any given page. Of course, I still provide an overall evaluation based on content. I also select only one paragraph to mark for issues concerning explanation, argument and evidence.
Instead of encouraging students to revise an entire paper, I give them the opportunity to come to office hours with a revision of one or both of these selected paragraphs. This can easily be read together in office hours and presents a good learning opportunity. It also allows the student to do some revision without getting behind in class because she is trying to tackle a major revision of a whole paper.
I should say that given my small class size, I also give them one opportunity to revise one whole paper if they wish. But for larger classes, this might be a good way to 1) recognize the value of revision, 2) make revision targeted and effective rather than a daunting and distracting process, and 3) encourage us as teachers to remember that writing lots of similar comments across a whole paper is as demoralizing to students as it is frustrating for us.