Demystify writing for your students. Use writing samples in your rubric so students can see what kind of writing is expected at each different section of a rubric.
*** you will need to collect a wide range of student samples of writing to use with this criteria.
A lot of the time, students have a difficult time with writing because they cannot decode or figure out what is expected. Using this criteria and matching it with a writing sample that is "true" of that criteria helps them figure out expectations, where their own writing is on the scale, and what they must do to improve their writing skills.