I've attended conferences before and met a few people here and there, but this time I approached the event differently.
First of all, I volunteered. Let me recommend this to anyone who's interested in going to a conference but doesn't have a lot of disposable cash to pay for it. By volunteering and agreeing to "greet" people in the halls between sessions and help direct them to their next destination or to serve as a hostess ready to adjust the temperature in a room should it get too hot or cold, I got to attend for free. That's right, free. I was slightly late to sessions and had to leave just before they finished, but otherwise I was just like a regular attendee. Except everyone talked to me. I wasn't just another face in the crowd, I was one of the volunteers, and that was a great icebreaker.
Which brings me to my second point, enjoy a good meal. Some of the best conversations I had with other writers was over breakfast. I learned about their projects, their work habits, the other conferences they attended. I got recommendations for writing software (Scrivener is hugely popular) and their take on how to make contacts at conferences (talk to editors instead of agents, then you can name drop editors who like your work when looking for agents). Most of all, it was wonderful to hear the other writers facing the same blocks I face - time, distractions, plotting the middle of a book - and I felt so much better to know I wasn't alone.
Finally, I brought contact cards. I've done that before, but this time I wasn't afraid to pass them out. After all, what good is it to meet all these great writers, editors, and agents if you never connect (or at least remember their names) again? I'm hoping to hear from the new friends I made last weekend.