Type a template for each student's art projects, with the student's name and the following sections: medium skill, visual elements and composition and balance. Apart from these sections, include anything else that you want the students to improve upon during the class. Goshen College professor Marvin Bartel suggests grading art projects on "longitudinal assessment," meaning to grade projects based on a student's progression in skill, rather than by comparing with other students.
Assign importance to each section, using percentages. Importance can change per project or remain static over the course of the school year.
Grade the skill in the artistic medium using your school's grading scale. In elementary school, each project likely explores a different medium, so determine to what level the student mastered the techniques you provided.
Grade the student's skill in the visual elements of color, value, shape and form. Compare the visual elements with prior projects. Superior grades show a significant jump forward in use of these elements, while good grades show movement forward in learning. Average grades show no movement forward and below-average grades show little or no effort and possible regression. If you feel the student moved backwards in visual elements, try speaking to the student before assigning a grade and examine his artistic process.
Grade the student's skill in design and composition elements, such as emphasis, harmony, unity and opposition. Compare the design and composition elements with earlier projects and score in the same way as you score the visual elements.
Grade the student's skill in presenting artistic balance (symmetrical, asymmetrical and radial). Compare elements of balance with prior projects.
Grade the project on any other criteria that you deem important for the classroom's goals.