Cover letters can be used to compliment your resume. Their purpose is to add value in explaining how your experiences and skills are a fit with the job to which you are applying for. Below is a sample cover letter format that you can use as a tool to help you create strong cover letters.
SAMPLE:
Your Street Address
City, Province, Postal Code
Phone Number
Email Address
Date
Employer Contact Information (if you have it)
Company Name
Address
City, Province,
Postal Code
Salutation
Dear Mr./Ms. Last Name, (leave out if you don't have a contact)
Body of Cover Letter

To let the employer know what position you are applying for

Why the employer should select you for an interview

How you will follow-up
First Paragraph

Why you are writing

The position you are applying for and where you found the job listing

Something to arouse Interest – ex. name of a mutual contact or if you have specific training or experience that would be relevant to the position
Middle Paragraph

What you have to offer to the employer in terms of skills/qualifications
-- customize each cover letter to match the skills/qualifications that are required for the job that you are applying for

Provide examples/explanations of when you successfully used these skills/qualifications
-- use the STAR formula to explain your points (Situation, Task, Action, Result)

In this paragraph make sure you are interpreting your resume and not repeating it
Closing Paragraph

Thank the employer for considering you for the position

Mention that your resume is attached for their review

Let them know that you look forward to hearing back from them about this position
Complementary Close
Best regards,
Signature
Your first and last name
COVER LETTER RULES OF THUMB:
1. Research the company and position
Referring to something about the company shows you are really interested
2. Tailor your letter
Highlight skills you have that are a requirement for the position
3. Keep it short and simple
Concise and to the point (max of 1 – 3 sentences per paragraph)
Simple, direct language (reflect your individuality but always maintain professionalism)
Positive and enthusiastic tone
Minimal use of personal pronouns
4. Support your claims with accomplishments
Add value through touching on highlights from your resume, but be careful not to repeat it
5. Always check for spelling and grammar