Cover Letter Fundamentals

Because the cover letter is usually the first thing a hiring manager sees, it serves as the primary enticement for him or her to read your resume. For this reason, it's wise to spend as much time perfecting your cover letter as you would your resume. Consider the following pointers to ensure yours has maximum impact:
Make it specific to the job. If your cover letter reads like it could accompany an application for any job, you are unlikely to get an interview. Hiring managers are looking to understand why you would be right for their position and company, so demonstrate how your strengths and accomplishments match the job requirements.
Also address your letter to the specific hiring manager, rather than using a generic introduction. If you don't know the person's name, call the company to find out.
In addition, research the firm by reading industry publications, searching online and talking to members of your professional network. You can then demonstrate your knowledge of the firm as you explain how your skills and background are a fit.
Avoid rehashing your resume in the cover letter. Look at your letter and resume as separate but related documents. They should complement one another without being overly repetitive. Although you will undoubtedly need to mention past positions, employers or experiences in your introductory note, use slightly different wording and a more conversational style than you would typically use in a resume.
Key in on key words. If the position for which you're applying calls for a professional who is "highly organized" and has "exceptional communication skills" and you possess these skills, use some of the same language in your cover letter.
Keep it brief. Your letter doesn't have to be lengthy to be compelling. A good rule of thumb is two to three paragraphs for e–mail and three to five paragraphs in print.
Proofread. Carefully review your cover letter for flow and proper grammar. Ask others to proofread and critique it as well.