1.  Write the letter to the person you think is the one who would hire you.

2.  Research!  Demonstrate that you know something about the reader's company, something that you had to do some research to find out.  Such information can be found on web sites, in annual reports, in your local newspaper and/or business journal, in trade magazines, etc.  Customize your letter to a particular company.  This will impress and make you stand out from the pack of job-seekers.

3.  Explain what you can do for the company, not what you want the company to do for you.  Begin by stating some specific way in which you can help the company or department accomplish a particular goal, preferably giving an outstanding example of a related accomplishment.

4.  Be specific about the job you want.  Hirers want you to have already done your homework and figured out exactly what job you want.  The time to explore other opportunities within the company will come, during the interview if/when the interviewer takes the initiative to ask you about your other options.

5.  Quantify your accomplishments.  After your initial attention-grabbing statement of how you can help the company and stating your greatest related accomplishment, list four or five additional accomplishments, bulleted and quantified.  For example:  Rather than-- "Worked with sales team to increase sales effectiveness", say "Responsible for increasing team sales by 37% in two years."  Your numbers can be approximations, so long as you can explain their rationale if requested.  Think of quantifications involving estimated cost savings, contribution to a company's bottom line, employee retention, specific intitiatives, etc.

6.  Mention accomplishments that directly relate to the job you want.

7.  Keep it brief, succinct and simple.  Your cover letter should be short and to the point.  It should be just one page.  Remember, you are trying to capture the reader's interest in knowing more about you.  Telling your life story is boring.

8.  Is it visually appealing?  When you've finished writing your letter, take a "big picture" look at it.  Is it visually appealing?  Is there plenty of white space (using bullets increases the white space)?  Does it look uncrowded?  Does it look like a letter you would want to read?

9.  Close with an invitation to the reader.  You are writing this cover letter to get an interview.  Tell the reader you would like to talk or meet and include these words: "Please give me a call at such-and-such a phone number."

10.  Follow up with a phone call or a second letter.  People get busy and can get sidetracked by other priorities.  Don't assume that someone isn't interested just because she or he doesn't call you after your first letter.  Give the person a call if possible; if you can't reach him or her, write a second cover letter reminding the reader of your first letter but adding some new quantified accomplishments.  Again, ask the person to call you and give your phone number.