There will be plenty of people at the conference worried about the same exact thing you are. So by coming and talking to them, you will likely be doing them a favor. Now they can talk to you and not have to pretend to check email.

Once at the conference, people will ask you what it is you do, where do you come from, and other ice-breaking questions. Think of a longer answer to these questions that give the other party a chance to keep the conversation going. For example, instead of saying, "I am a software developer" you may say, "I work as a software developer in this small agency in Chicago, and in my spare time I am working on a pet project that's going to help developers keep track of bugs." Now people can tell you that they've been to Chicago or how much they hate/love bug tracking tools. And you take it from there.

What I found easiest is try to be a part of group conversations. This way the weight is not entirely on you to keep the conversation going, and you may instead jump in here and there as you feel comfortable.

Good luck!