For instance, if the interview subject offers to hook you up with a hiring manager, you should only accept such an offer if you are truly interested in applying for a job. If you are unsure, it is better to thank the person for the offer and say that you will be in touch. Informational interviews are not meant to be job interviews, and indeed it is a giant faux pas to ask someone during an informational interview for a job. Yet, good talent is often hard to find, and sometimes interviewees are thinking of their own organization's needs whenever they are talking to new acquaintances. Finally, after the interview is over, send a thank-you note as soon as possible.
Many people are quite happy to receive such a note by e-mail.
Yet there are still many pockets of civilization in which a handwritten, snail-mail note is still the gold standard. Keep track of the people you've interviewed. It may help to know who told you what. And sometimes interview subjects will develop a personal interest in you and your career aspirations. They will appreciate hearing updates from you periodically.