Aside from excellent organization of thoughts and an engaging writing style, you can make your cover letter stand out in a number of ways:
Make every effort to address your cover letter to a specific contact person, using name and title. Avoid using “To Whom It May Concern.” If you find it impossible to get a name, at least use a title that will direct your resume and cover letter to the right person, for example: “Dear Internship Coordinator” or “Dear Hiring Manager” or “Dear Outreach Director.”
Be creative about finding a contact name. Check the web site. Call the organization and inquire. Ask someone you know who works there to check around for you.
Show your understanding of professional standards by formatting your letter either in business (block) style or personal style. The difference is that in block style, all components of the letter begin at the left margin. In personal style, the return address, date and complimentary close begin at the centerline of the page, and paragraphs are indented 5 spaces.
Accentuate the positive. Avoid qualifiers that might imply hesitation or lack of confidence. For example: Before: I may not have all the experience you would prefer, but I believe that my enthusiasm and willingness to learn make me a strong candidate. Better: I believe that my enthusiasm and willingness to learn make me a strong candidate.
Use strong, active verbs – avoid the passive voice. For example: Before: The presentation was given at last year’s annual meeting of the Independent Filmmakers Association. Better: I gave the presentation at last year’s annual meeting of the Independent Filmmakers Association.
PROOFREAD. Ask someone you trust to proofread also. Don’t rely solely on your word processor’s spelling checker. Mistakes in spelling or grammar can send your application to the reject pile.
Avoid overblown language and excessive use of adjectives.