After you have read and watched, go through the papers you have written while a graduate student.

After you have read and watched, go through the papers you have written while a graduate student. Pick out a paper with some substance, that is, a paper that you spent some time working on. There is no need to edit or otherwise try to improve the writing, nor do you need to try to find a more difficult or less difficult writing sample in the hope that you can manipulate your scores. That is not the point of the exercise. There are no wrong scores here.