I saw Andy Lopata speak at the Wellbeing Network yesterday and he delivered a thoroughly entertaining, informative and interactive session on practical networking.
You can get some of Andy's thoughts at his blog.
One thing he said rang true for most of the audience. He said "When someone asks you 'what do you do?' at a networking event, it's the networking equivalent of 'do you come here often?'"
He then went on to explain how important it is to build relationships first. As you build on those relationships you can then communicate exactly what you do and how you make a difference. Good Networking!