Sample
[DATE, ex. Friday, February 10, 2006]
[NAME, COMPANY AND ADDRESS, ex.
Robert Brown
XYZ Inc.
1234 First Street
Suite 567
Anycity, Anystate 85245]
Dear [NAME, ex. Robert Brown],
I would like to thank you for recommending [FIRM NAME, ex. Bill's Carpentry Inc.] for [PURPOSE, ex. renovating our offices]. [STATE WHAT YOU WERE PLEASED WITH, ex. I was indeed pleased with the results; their craftsmanship is unparalleled and our office now looks modern and up-to-date.]
Thanks again.
Best regards,
[YOUR NAME]