Informal Meeting with Prospective Mentors at a Conference - How to Prepare?
Be knowledgeable: know the mentors’ research papers and themes. 
Be curious: prepare a few good questions to ask the mentors. Get them to talk about themselves (there’s nothing professors love more than talking about their work!)
Be forward thinking: what would you do to improve their work? What do you bring to the table? What good ideas do you have? You don’t need a 5-step research program, but you definitely need to show you can suggest good directions for future work.
Be relaxed: or act like it. appearing nervous, profusely apologizing at every turn, being overly subservient etc will make you look bad. Talk to them like an equal. If your prospective mentor has such a fragile ego so that they need you stroking it, they’re probably not fun to work with.


Good luck!