Informational interviewing is a form of networking. Begin by making a list of everyone you know, including friends, friends of friends, your parents' friends, classmates, professors, etc. You may find a connection through someone you already know.
If you are not able to identify someone through your existing network, you may have to reach out to people who you do not know via email or in-person. Keep in mind, most people enjoy helping college students and enjoy talking about what they do, so don't be afraid to ask.