Congratulating someone on his or her accomplishments is a positive way to get your foot in the door. Reiterate their accomplishment, suggest how your product or service might help them and finish with an action item.
1234, Main Street
Boston, MA 02123
08 April, 2005
<Recipient Address Goes Here>
Congratulations <on the accomplishment>. It's always gratifying to see hard work and talent get rewarded.
One thing I'm sure you've learned along the way is the importance of good business relationships and working with people you can count on. This not only makes your job easier, but it reflects well on your good judgment. We at Abc Company are dedicated to providing <product or service>. <Benefits of product or service.>
I'll call you <time> to <desired result>. I look forward to speaking with you and exploring how we might meet your needs. Again, congratulations and continued success.
encl: <List of enclosed items goes here>