Our unofficial playbook is this - If it's a high profile or generally higher stature individual, do some homework prior, then meet them, introduce yourself and explain your background (research/work experience/educational path). Essentially an elevator pitch. If they're interested in learning more, they'll ask more in-depth, probing questions that they'll relate to their past experiences. If not, they'll usually say something like "great to meet you", ask surface level questions out of courtesy, then engage someone else while saying it was their pleasure.
If it's someone other than a big shot, take the initiative and ask questions to learn more about the other person. Typically they'll ask similar questions of you, and then you'll be off on making good connections. Use networking events to get a first hand experience of the myriad of personalities that exist out there so that you can identify certain types in your future careers. These events can also help to look at situations from new angles, and can help you see ways that your future career can take on new forms. Would you be interested in doing research? Or working with the Joint Commission? Or maybe lending time to volunteering with an NGO? The best way to figure things like this out is to network, and run into folks doing these things at these events.