A great cover letter for a job as an assistant teacher is unique to the specific job opening, school or teacher. It explains the applicant's qualifications, tells how the school or teacher would benefit from hiring the applicant and showcases the applicant's interest and knowledge about the school and position.
The first paragraph should explain the purpose of the cover letter. It could be written in response to a job opening, or it could be designed to inquire about possible openings. The first paragraph should explain how the applicant found out about the job or school or how he learned about a specific teacher and her methods. For example, the first sentence of a prospecting cover letter could start like this: "I read your profile in XYZ magazine, and your teaching methods inspired to want to work in this field."
Cover letters should not be more than one page long, and they should use the same standard font and size as the resume being submitted.
The cover letter should also expound on any relevant experience, volunteer opportunities, licenses or certifications discussed in the resume. The applicant's teaching philosophy, computer skills, grade levels taught and tutoring experience should also be included.