Establish your relationship with the candidate. Explain the capacity in which you are qualified to recommend him as a student teacher and the length of time you have been acquainted. If you were a professor from an education course, mention the candidate's achievements in the course as well as her ability to collaborate with classmates, if relevant.
Describe the prospective teacher's personality. Highlight traits, such as reliability and responsibility, that will encourage the master teacher to accept him for this fieldwork. Include anecdotes that illustrate the candidate's positive traits.
Describe the aspiring teacher's ability to work with and connect to children. Highlight the candidate's previous teaching experience, if any. Include experience teaching after-school programs or volunteering as a Big Brother or Big Sister or similar activity.
Tell about any talents that the candidate possesses -- such as experience or an interest in one of the arts or sciences -- that will make her a unique asset to both the classroom and school community.
Conclude the letter on a positive, upbeat tone. Summarize your points briefly and state affirmatively that you recommend this person for student teaching. Sign the letter and include your contact information.