Write a letter thanking for the Informational Interview
I would like to express my gratitude for the informative discussion we had yesterday in your office. It was especially useful to have my questions about the field of (topic) answered by someone with your experience and training. I was delighted with the opportunity for the tour of your work facility and see people at work on such a variety of projects first hand.
My discussion and tour have helped me to clarify my career plans. I am more determined than ever to pursue a sales career. I shall soon be getting in touch with people recommended by you.
Thank you again.