Many people pay a good deal of attention to their resumes, polishing it and tweaking it to an inch of its life. What they could do instead would be to leave the resume alone after a while, and try to get a better impression in with a cover letter. When you have one of these and it is written in superior style, is well-designed and is just made with the recipient in mind, it can be so powerful an impression, getting hired could just be in the bag. But you do need to know the how to. Cover letter competence doesn't come easily to everyone. If you just slap one together and let none of your creativity show through, or if you don't specifically address it and target it at the hiring manager who will be reading it, a cover letter can have no effect at all.
There is no real reason to dread the prospect of getting down to writing a cover letter though. This is the one place in the resume writing process that you actually get to let your hair down a bit. There is no strict format you are asked to follow, and for this reason, you can easily find a way to bring up things about yourself that in a regular resume would be hard to accommodate. Your special little skills, your unconventional successes, and the things about yourself that make you proudest. If you always wanted a place to talk about all of this but never knew how to, cover letter freedom was made for you.
So how do you make the best possible use of the freedoms that the cover letter offers you? There any number of things you could do. Try to put your qualifications and special skills into perspective by matching them to several of areas you know the company deals in or is worried about. Learn a little bit about the company - its mission statement, it's slogan and so on, and try to use them in the first paragraph of the cover letter in some clever way. One of your main aims with a cover letter is personalizing your resume for a specific hiring manager. Ideas like these will endear you quickly to the people in the company who make the decision.
And as always, testimonials from people who know you did happen to hold positions of authority, are always welcome. The how to of a cover letter is all about personalizing your resume to yourself and to the company. And it's about how you make use of the opportunity.