Interview the student. Ask the student about her ambitions, career goals, extracurricular activities and leadership positions. This interview need not be extensive, but it allows you to gauge the student's interests, gives you an idea of her character and helps provide direction for the recommendation letter. As an alternative to an interview, you can request the student's resume.
Request that the student provide you with the name of the recipient, or address the letter as "Dear Selection Committee."
Provide background on your relationship to the student. Detail how long you've known the student and what classes the student has had with you.
Write a letter explaining the student's character and academic skills. Highlight his academic performance in your class. Examples of character would include assisting other students, engaging in classroom discussions and maintaining a good attendance record.
Provide concrete examples to back up each assertion of character and skill. These examples can be from his academic performance in your class or from information gathered in the interview or from the resume.
Personalize the recommendation. If you are aware of any personal adversities the student has overcome, such as a learning disability, be sure to mention them. Any awards or honors the student has received should also be mentioned, especially if they are related to your class or her intended field of study.
Tailor the recommendation around the student's intended major or field of study. Although you may be an English teacher and the student intends to study biology, you can still offer a helpful recommendation. For example, attention to detail and analytical and research skills are useful for any field of study.