When the big shot is explaining what his kids did last week, ask if he knows a generalization of some exotic theorem.
Bring a laptop and a thick notebook, preferably 3/4 full of very technical looking material.
Do not squander your visual attention in keeping eye contact with the person with whom you are conversing; there may be a bigger shot coming by soon.
Do not presume that any conversations at a conference are private; the people would not have come to the conference if they did not want to talk to you – feel free to interrupt any conversation.
Bring a copy of your rejected paper and pass it round for comments.
When in doubt, talk about the weather especially if there are Britons at the table.
Exploit your big shot status to gain a competitive advantage in the ruthless competition for the attention of the few female researchers who are at the conference.
A good opening line is “what paper are presenting” or “how was your flight?” [make sure the big shot flew and did not drive].
Engage in gossip about other researchers in your field including how bad other papers at the conference are. Gently sound out the other person’s views before slagging off too severely.
Have a life, in order that you have topics of conversation to engage in other than technical ones.