Determine the purpose for the writing assignment. Which writing skills do you want to measure on this particular assignment: Ideas and Content, Organization, Voice, Word Choice, Sentence Fluency, or Mechanics? You might decide to measure all six traits or only three; the choice is up to you.
Describe proficiency in each trait you have chosen to measure. What do you want to see from your students in that category? For example, if you chose to grade for Organization, you might want to see: 1) transitions between ideas and paragraphs, 2) a logical order to the ideas and arguments, 3) support given to main ideas. You may want to refer to writing standards set forth by your state when creating these descriptors.
Describe the other levels the student could achieve. These are usually Advanced, Partially Proficient, and Unsatisfactory. In the Advanced stamp, the skills should go beyond those described in the Proficient stamp, where the student has excelled beyond the skills taught in the classroom. The Partially Proficient stamp describes skills that may be lacking in refinement, and the Unsatisfactory stamp describes a lack of skills.
Assign a point value to the skills levels. It may be easiest to prescribe 5 points to Advanced, 4 to Proficient, a range of 2 to 3 points to Partially Proficient, and a range of 0 to 1 points to Unsatisfactory. This grading scale allows for some teacher discretion in grey areas.
Write an essay to the assignment and grade your work using the rubric stamps you created. This is the most effective litmus test for the effectiveness of your assignment and rubric.