Personalize By Printing 

If you want to include personalized, handwritten messages on your thank-you cards, you should print one side uncoated. The artwork side can be printed on a glossy or matte-coated sheet, while the other side should be uncoated so that your pen ink can soak in.

Choose a premium cover stock, such as 13-point recycled or super-thick 16-point matte or gloss stock – if you're not sure what different paper stocks and finishes look and If you like, you can order a free preview of various paper stocks to help you determine.  

Obtain a Hardcopy Proof

Few things are more humiliating than sending out six dozen "Thank You" cards to everyone on the list. Hard-copy proofs are important for ensuring that it looks exactly as expected and is perfect.

Consider a hard-copy evidence an investment in a good thank you card mailing. It's certainly worth a few dollars now to save big headaches (and more money) later.