I find that if I ask students to revise their work based on my formative feedback, some of them do make the changes and others do not. However, if the students have to create a Change sheet, they do make the changes. In the Change sheet, they list the original learning problem, tell what they did to improve, and include an example from their most recent work. As I look at their revisions, I first look at the original rubric, then their Change sheet, then put their previous work and their revised work side by side. I look for the changes in their revision. I look to see if they have changed all of the items for each formative feedback. For example, if I asked a student to improve his/her topic sentences, I look to see if all the original poorly done topic sentences have changed. If students have made the revisions for the three major areas of feedback and, therefore, reached the level of proficiency or above proficiency, they receive a new higher grade.
How do you help your students to improve?
My book, Formative Assessment: Responding to Students, is available through Eye-on-Education.
Education with Technology Harry G. Tuttle 
I like the idea of a change sheet. I just graded our new wiki for the first time last week, and I would like to see more of the kids do what they were asked–you gave me a great idea.