Your letter should not be longer then one page but only in the rarest of situations your letter can be longer than one page and considerably less than a page is good enough. About four paragraphs should do the trick. The first should acquire attention, tell why you’re writing, and tell what you want to do for the company. The second should establish your Unique Selling Proposition. The third should further boost your qualifications without going over your resume.
The final paragraph should request for an interview, tell how you plan to follow up, and thank the employer for considering you. In case of answering an advertisement; you may need another paragraph or two to show your qualifications to the job requirements. Your letter should not be too short and it is also concise and pithy. Edit your letter unkindly. Follow the journalist’s philosophy and try to write tight! Cut out all unnecessary words and jargon. Then go back and do it again.