Wednesday, September 19 is National Gratitude Day. Show your thanks with pretty, elegant thank you cards - the kind that are so nice you start looking for excuses to exit e-mail and get out a pen.

Whether or not you know it, you’ve probably seen the work of Italian graphic designer Louise Fili: on packaging for Williams-Sonoma and Sarabeth’s jams, in a mark for Tiffany & Co., and on ...