Come with friends though and your all set. All I know, be assertive and active and people tend to come to you.
I did go to a little video game convention-ish thing last year (Rezzed) with some friends, and it was nice to have that sort of back-up of "you know there are some folks who you can hide behind in an emergency" to make the "making new friends" thing easier. I didn't really make many new friends though, but I'd spent a week making a Quaggan hat from Guild Wars 2 beforehand, and folks came and said some nice things to me about it, and so it was sort of sociable and I'm waffling now sorry.
BUT BEFORE I STOP WAFFLING, oh god, I still think about this and smile so hard my face hurts. So I'm queuing up to get some food, because it's getting late in the afternoon, and one of my friends is queueing up with me because, well, hiding behind people in case of emergency and all that. We're talking about a game we wanted to go and try (I think it was in the Devolver Digital booth/area, because nearly every indie game I've ever got excited about over the last few years have been published by them) and I feel somebody pull on my jacket. I turn around, and there's this little girl, she's maybe seven years old at most, and she's wearing a Quaggan hat she'd made too.
And she was just so excited to see somebody else wearing one, and she explained how her mum helped her make it, and how she really liked Quaggans too, and it was just the sweetest thing I'd seen. She asks what I used for the eyes on my hat, and told me how she picked the colours that matched the hat her character wore, and it was just so wonderful to see this little kid with all this enthusiasm.