Phone call with alumnus?

my aunt bumped into an old friend from college at my graduation a few weeks ago and introduced me. this friend not only happens to be an uncle of one of my friends but also a trustee of our alma mater (also an alumnus). i graduated with a master's in finance and only have a summer internship for now looking for something full-time. i learned that he is one of the founders of a small investment firm and had been with goldman sachs for many years so i got his card, emailed him a week later and have set up a phone call with him. he asked me to send my resume and a sample cover letter so i did. this is mainly an informational/networking conversation...any suggestions for how i can get the most out of this phone call? questions? etc?