Decide with what you want to evaluate the class. Depending on the style and subject of the writing assignment, the rubric will differ. For instance, if you are a biology teacher grading your students on a lab report, then the rubric will be different from an English teacher's poetry rubric.
Address what each student should have learned through lecture, class work and homework. If one of the initial lesson goals was to develop the use of imagery in short stories, then write that down. You should have at least 20 goals for the student divided into five categories. Common categories include ideas, grammar and spelling, presentation and research.
Organize the categories from most important to least important. Assign point values to each goal and category. In total, the values should add up to 100.
Write the objectives clearly and concisely under each section. Leave no room for interpretation.