The standard format for writing thank you letters includes:
1. a heading with the recipient's name and address.
2. the name of your scholarship or the position that you applied for.
3. the salutation: "Dear ________" using the formal name of the donor or interviewer. "Mr." or "Ms." is correct for untitled individuals; if the recipient possesses a doctorate, "Dr." is appropriate.
The first paragraph states your purpose: to thank the scholarship sponsor for his generosity or to thank a job interviewer for his time and courtesy. It should be no more than two sentences detailing your appreciation. The Warriners format adds a second paragraph that details interview highlights, compliments an interviewer on his courtesy or mentions the financial need the scholarship will address. In either case, a second paragraph should include information reminding the recipient about you and your enthusiasm, either for the position for which you interviewed or the scholarship you will receive.
The final paragraph should reiterate your interest in the position offered, or, if the thank you is for scholarship money, your commitment to use the investment wisely. As with the opening paragraph, you close with a "thank you" to the recipient; you can also repeat your interest in the position or your happiness with the donor's generosity at this final juncture. You close the letter with "Sincerely" only, nothing more, and then your signature.