I have created a "blanket" rubric for assignments students complete online. We discuss the rubric at the beginning of every year for student input and changes. For example this year I will be implementing some type of "global communication" score into the rubric. When a student completes an assignment they use the rubric and grade their own work and hand it into me (grading their own work is a score in the final rubric I use). I then grade the assigment and we discuss our differences. You may have to change the rubric as the year progresses and the students' skills increase.