Avoid nervous jokes, and resist the urge to confess your insecurities about teaching. Decide how much composition theory you want to include. It makes sense that you should make natural and logical connections among your pedagogical principles, course-goals, and classroom practice. These are just some ideas to get you started. Use lively language which draws pictures in your readers' minds and appeals to their senses and their sense of humor.
People like to imagine a human being applying for a job at their school.