A cover letter should accompany your resume to introduce you to a prospective employer as a knowledgeable and capable applicant. Cover letters are used when applying to a specific, advertised position. Here is a sample format to assist you:

Format of a cover letter

Today's date

Your name

Your street address

City, province postal code

Name referenced in job ad, and title of person

Organization

Street address of organization

City, province, postal code

Dear (name referenced in job ad), 

First paragraph

• Name the position you are applying to and where you saw/heard about the advertisement,
• Write a statement summarizing the benefits you bring to the employer,
• State what interests you in the organization and the position,
• Provide a potential starting date.

Middle paragraph(s)

To prepare this paragraph think about – here’s what the organization is looking for, and here’s what I can offer - to enable you to organize ideas.

• State how you can meet the employer's needs (not how they can meet yours).
• Match the words used in the job description
• Document your qualifications by themes and back up your points by using examples
• Organize paragraphs by putting the most important ones first
• Focus on your strengths; highlight them in such a way that the employer can clearly see a connection with their organization. 

Final paragraph

• Refer to your enclosed resume
• Mention you would like an interview to provide more information
• Include your phone number with the best times to reach you, and your e-mail address

Sincerely,

Your signature 

• One page is the maximum length for a cover letter.
• Avoid the words "as you can see" when describing ideas and concepts, because the reader may not be able to "see" the point the way you do.
• Check your first draft for the number of times you have written "I". Overuse of "I", monotony of sentence structure, and rambling text defeat your goal of writing an effective letter.
• Try to limit your paragraphs to no more than four or five sentences and your sentences to a maximum of two lines, where the first sentence in a paragraph introduces the topic to be covered in that paragraph.
• Send originals, not copies that look mass-produced and impersonal.
• Use high quality 8-1/2" x 11" paper (same stock as your resume).
• Ensure a neat, uncluttered and well-organized appearance.
• Edit your draft for clarity, tone, accuracy, proper spelling, punctuation, and grammar.
• Send your letter and resume unfolded in a large envelope.
• Keep a copy of your correspondence.