Likewise, be very selective in what you choose to go to. I find "networking events" are often a waste of time, but making friends with somebody you know has something offer and, say, going out with them and their friends, can have a high ROI indeed.

General rule: the more exclusive the event, with 1-on-1 hang-out being the most exclusive and Meetup.com being least exclusive, the better.

But, yeah, otherwise, (1) be a shark (at first) and (2) don't forget that real networking is based on actual friendship / respect.