The purpose of the cover letter is to overall, summarize why you would be the
best candidate for the position that you are applying for and to also further
explain details on your resume that may call your candidacy into question, such
as gaps on your resume or very brief stint with a particular employer.
Format
A typical structure for a cover letter is 3-4 paragraphs.
1st Paragraph: Include how you found out about the opening along with some
basic information about yourself.
2nd Paragraph: This is the paragraph to include why you are interested in
the position. Further include relevant accomplishments. Also, this is the
paragraph in which to explain other items on your resume in detail.
3rd Paragraph: In this paragraph, express your interest in the
opportunity for a interview, etc. Also offer the employer additional
documentation of success along with references and letters of
recommendation.
In conclusion, thank the reader for consideration of your resume.
Content
Make sure that your cover letter is addressed properly to the intended
recipient.
If there is a 3 year gap on your resume, this would be the place to explain
why that is the case (Paragraph 2). Do your best not to repeat information
that is already on your resume.
Include information about availability for an interview
State willingness to travel or include further information regarding
willingness to relocate or specific relocation choices.
Highlight points that match the company's hiring requirements