1. Write the note on a typewriter or word processor using your letterhead. Avoid sending store-bought thank-you notes.
2. Address the note to a particular person who has helped you or rendered a particular service or favor. Use his or her formal name and title on the address line.
3. Use a more informal greeting ("Dear Bob," "Dear Sue") if you are on a familiar basis with the person you are writing to. Otherwise, the greeting should reflect the person's formal name ("Dear Mr. Jones").
4. Explain who you are and what the note is about in the first few lines. Make reference to the service or favor that has generated your thank-you note.
5. Use professional language throughout the note and a personal, breezy touch.
6. Keep the note as brief as possible while maintaining a tone of friendliness, especially if you are personally acquainted with the person.
7. Close with your formal name and title on the signature line. If you know the person well, sign the note by hand using your first name. Otherwise, sign your full name.
8. Enclose your business card if no prior relationship exists with the person you are sending the note to.
9. Address the envelope using the recipient's formal name and title.
It can also be appropriate to send flowers or some other thank-you gift if someone has really gone out of his or her way for you.
Interviews should be followed by thank you letters from the applicant! E-mail is not appropriate for this!
But what if...
Sending a thank you note to an interviewer via snail-mail is a nice personal touch, but what if the position is to be filled within a day or two? An e-mailed thank you note will ensure it gets there on time. Or, you can always hand-deliver a paper thank you note to the receptionist the next day.
Warnings: Avoid excessive familiarity if you do not have a personal relationship with the recipient.