Keep your note short and simple. Follow the four sentence rule:
Write clearly and carefully in your very best penmanship.
Always include a salutation: "Dear Mark." It is the same as saying hello.
For a closing, write "Sincerely," "Best regards," "With love," etc, depending on how well you know the person.
Write the date at the bottom of the note in the left-hand corner.
Proofread your note thoroughly before sending.
When addressing the envelope, always use Mr. or Ms., never just a first and last name.
Try to send out a thank-you note within 24 hours of receiving a gift. If you have let some time pass and still have not sent out a thank you note, you should still send it out.
Thank-you notes are not an out-dated gesture. They are still in practice, easy to write, and very much appreciated by the recipient.
If you still have not sent out your thank you notes for gifts you received last year, time is ticking. Get those thank you notes sent out ASAP!