How much do you want a job? Cover letters are equally important as a résumé since résumés tells reviewers where you’ve worked and a brief description of what you’ve done; a cover letter tells reviewers how you think and how well you write and express yourself…and to the surprise of many job hunters, it often is the deciding factor on whether you’ll be called for an interview or not.
I’ll give you a great example: Peter S. was looking for a job as a medical care x-ray technician and applied for a position that he was considerably underqualified for. His résumé and experience were light, but he wrote a sentence in his cover letter that put him at the top of the applicant pool and got him hired: “I treat all patients with respect and dignity.”
Like résumés, cover letters should be customized for the job you’re applying for—never user a generic one since it shows that you’re lazy. Also, don’t rehash what you put in your résumé but expand upon your experience from it that would apply to the position you’re seeking so a reviewer will get a solid idea of what you’ve accomplished and what you’re capable of doing. Just be sure to proofread your cover letter thoroughly—it only takes one goof in it to give a reviewer an excuse to not include you in the interview pool of applicants.
When submitting a cover letter online, format it as if you were sending it by surface mail: include the current date at the top, the recipient’s address, salutation, content, and finally your contact info*. That way, if a reviewer prints your cover letter, s/he can associate it with your résumé; if it gets mislaid or misfiled, it would be a chore to try to identify you just your e-mail address.
There are a zillion articles on the ‘net about how to write outstanding cover letters—be sure to read some of them and glean their wisdom!
*It used to be that you’d put your return address in the upper right corner of the page, followed by the date, but that’s old school; your name, address, e-mail and phone are better placed at the end of the document at the left margin—it makes it easier for people to copy your contact info into a computer.