Set a grading scale for the project. Some teachers use a wording system, such as poor, fair, good or excellent. Other instructors assign a number score to each; poor = 1; fair = 2; good = 3 and excellent = 4.
Divide the diorama project into sections that will be scored separately using your number or word scale. Include content, organization, creativity and grammar or spelling, if applicable.
Define what constitutes a score for each number or word on the scale. Do this for each category. Include what level of performance will garner each score. For example, spelling mistakes, sloppy work or an inaccurate representation of the subject lowers a student's score.
Design a printed rubric. Using computer software, make a chart that lists each category down the side and the number or word scoring across the top. Fill in each section with the applicable information. Print copies and provide them to your students.