You know you need to do it; you can't stand there alone the whole time. If you don't, why are you there?
The "it" I'm referring to is starting a conversation with another person. For some, it's as easy as, well, smiling. For others, it can be nerve-wracking.
Start off by introducing yourself -- first and last names, please. Isn't that how you want to be known?
Ask open-ended questions. Is this the first time the person has attended the event? What made them attend? What do they like about the group? Are they local to the area? I live in the Pacific Northwest and have found that many people have moved here from out of the area, which always makes me curious about where they are from and what brought them here.
Pay a compliment. Personally, I find it a lot of fun to tell a stranger how much I like their shoes, jacket, tie, bag, or even smile. I always receive a smile in return and the conversation just seems to go from there.
Be prepared to say something interesting about yourself. For example, I say that I am a business etiquette and customer service specialist because I have found that it usually elicits a reaction of some sort -- comments, questions, sometimes fear ... However, if I say "I teach manners", well, that's basically the end of it.
Keep in mind that people like to talk about themselves. Ask a question or two, and then be quiet and really listen to the answer. Not only will you have a discussion going in no time, but the other person will think you are one of the best conversationalists around!