I can’t tell you how many truly awful letters I’ve had to read in my life. As a former administrative assistant, I was responsible for all the unsolicited submissions to a major New York museum. Artists and collectors all over the country (and abroad) wrote to have their work considered for display or acquisition, and to be honest the decision frequently rested more on the quality of their cover letter than on their work _ which, romantic dreams aside, rarely if ever sells itself.
Example: During the recent ARRGH convention in Washington, D.C., one of your sales representatives, Dusty Brown, informed me of a possible opening for a manager in your Data Center. My extensive background in programming and my master’s degree in information systems make me highly qualified for the position. In subsequent paragraphs, expand on the qualifications you mentioned in your opening. Add any appropriate details, highlighting experience listed on your resume that is especially pertinent to the job you are seeking. Close with a request for an interview. Proofread your letter carefully.