This is your time to be as sincerely thankful as possible. Adding a few lines that reference a conversation you had with the customer is appropriate. Do your best to avoid sounding rote, or making it seem like the same thank-you note is going out to a hundred people.

Mention that you hope the customer is happy with his or her purchase, and that you’re available if he or she has any questions or concerns. Ask the customer whether there’s anything you can do to increase his or her satisfaction.

If you’re writing your thank-you note on a card, be sure to mention your business name. If your thank-you note is written on letterhead, your company logo will be visible, so it’s not necessary to mention your name in the letter. If your thank-you note is in the form of an email, your company name and logo should appear beneath your signature.

Phrases like “we hope to do business with you again soon” sound like tag lines; best to leave these out. Don’t say something you wouldn’t say to an acquaintance. Don’t include a product pitch, a mention of an upcoming sale, or anything else that could be construed as an ad.

Use your best handwriting so the letter is legible. If you have too many thank-you notes to write to be able to write each one out by hand yourself, ask another employee to help you out. It really will be worth the time it takes to write out letters individually. If it’s impossible to write the notes by hand, you’ll need to find a different way to personalize them. At the very least, the customer’s name and your true signature should be included in each thank you letter. In some cases it might be appropriate to write a thank-you email, rather than sending a handwritten note. This can be appropriate when you have an established personal relationship with the customer. The key is to make sure it’s personalized and sincere. If there’s any chance your email could be mistaken for an advertisement, send a handwritten note instead.

Avoid using regular printer paper for a thank-you letter. Nice stationary really adds an extra touch. Choose thank-you cards that would be appropriate to send in any business setting. If your business is quirky and fun, it’s fine to use colorful cards that represent your company the way you want it to be represented. Avoid using cards with inappropriate or overly personal images or messages.

Small gift ideas include bookmarks, magnets, candy, a t-shirt, or a gift certificate. The gift should not exceed a $25 - $50 value. Some companies have ethics policies that actually disallow them from accepting expensive gifts.