Have you seen that thing on TV where the gal tells the nerd she wonders why he never asked her to marry him and he stumbles and says "Thank You" and she turns to butter?
The point of the message is that "Thank You" goes a long way to making people feel better.
Personally and in business, develop the "Thank You" habit.
While it is generally expected to send a written thank-you for gifts and special favors, it is also appropriate to send one for employment interviews and new business contacts. However, the most powerful thank-you note is the one that's unexpected.
Here are some "Thank You" points to consider
You should hand write it. With the exception below, don't use your computer to print it, or to print the address label and please don't use email for this most personal communication.
If you have that nifty computer font that was made from your own handwriting, your could slip the card in your printer. Be sure the font really looks like the way you write. Didn't know about this? There are several companies that do it, here is a link to one as an example only: http://www.theory.org/~strthrwr/fonts/custom
You can use plain paper, or you can use a thank you card. Some folks have personalized cards created, some buy them at the Hallmark. You can use a fold over card, or a single hard card in an envelope or a post card. It's not the messenger, its the message.
Be brief. All you are saying is Thank You. And say it only once.
No need to gush, be personal, say thank you and why.
Be sincere.
When you send a thank you note, it will have a great impact, "Because no one else does it"
