Rather than describe how to write a cover letter, I figured it would be more helpful to type one out as an example. There's no one way to organize a cover letter; I generally format mine into three paragraphs:
- PARAGRAPH 1: State the position you are applying for, organization name, and how you heard about the position.
- PARAGRAPH 2: Introduce yourself (e.g. Grade 11 student at Mountain High School) and describe your relevant skills and experience. If there is a particular reason you are interested in this job, you may want to state it at the end of this paragraph. If this paragraph becomes too long, break it into two shorter paragraphs.
- PARAGRAPH 3: Conclude with all of the "housekeeping" details -- that your resume is attached, that you can provide references, and that you are available for an interview. Make it clear who will be following up by stating either that you will be in contact with them (and when) or that you "look forward to hearing from" them. End with thanking them.
Good luck with your applications! If you have any questions about cover letters, resumes, or applications, feel free to leave them in the comments. Better yet, most schools and universities have career advisors who can be excellent resources.