Address the letter to the appropriate recipient of the college. Ask the student to provide you with the name of the addressee, or if this information is unknown you may write "To Whom it May Concern."
Write a brief introduction of yourself to describe the relationship you have with the student. For example, explain that you are the student's English teacher or math teacher, as well as how long you have known the student. This information adds credibility to your reference letter.
Discuss your experience with the student. Only include positive experiences, since this is a reference letter. Write about how the student performed in your class, level of academic expertise, how professional he or she is, in-class contributions, teamwork skills and other talents the student exhibited.
Include a section about the student's personal commitment to achieving goals, motivation to do well and what some of his or her potentials are. If you do not know this information about the student, then a sit-down conversation with the student is necessary prior to composing the reference letter, so that you find out what the student's interests and goals are.
Conclude with a couple of sentences about how well you believe the student would do at the particular college he or she is applying to. Make your support of the student clear. End with a sentence about welcoming the college to contact you with any further questions about the student. Always sign your name at the end of a reference letter.
Ask the student whether the reference letter will be sent with his or her college application packet, or if you are required to mail the letter directly to the college yourself in a sealed envelope.