A good way to go about meeting people is to start out by complimenting their cosplay (if they are, this only applies to cosplaying). If you like the series, you can say that. I've never met anyone that found that odd or off putting, in fact, that's how I have been approached before so..
Anyway, then you can tell if they wanna talk to you..They will either actually converse with you: "Oh awesome, yea this cosplay is my favorite character/this is my fav series/asks you your fav something"; or they will not engage: "Oh...Thanks (turns away)/Mmmhmm/Oh that's nice". That last part, I've noticed this happen..Someone will say "oh nice cosplay, this is my fav series" then the cosplayer "Oh, ok, thank you" then the fan of the series goes into a long one sided convo about how much they love it..The cosplayer will go "Mmmhmm/yea/oh" and not actually respond..Remember these when trying to talk to know who is and isn't willing to be a friend.
Another good way, like mentioned, is the gaming room. You meet a LOT of awesome people there that are very interactive with others. Maybe enter a tourny or something (not the event ones, but some people have little ones among people on games that are not in the event one). This is a good way to meet people. Also if you like a game someone is playing, and they are doing really good, when they finish, tell them. Say "Oh wow you're good at [game title]. This is one of the games I relly like." Usually they will want to also talk about the game with you. They just got all pumped up playing it so now they have energy. However if they are failing, this is a good chance to do something awesome. If you know how to play it, offer to help them.
I notice another thing that I'm gonna tell you NOT to do..Don't talk to people durring a sit down and pay attention event..Like panels, main events (contests, opening/closing ceremonies, etc), viewing rooms, and other similar things. They ar not going in there to make conversation. They are in there to pay attention to the people up front. A LOT of the "Otaku guys" (stereotypical bigger guy carrying around a naked anime pillow type guy, no offence to those that are not the problem ones) will literally go into these rooms and start talking to girls in their fav characters costume. It's the same thing with people that aren't "that person", but it's all the same, no one went there to talk.
Sorry this got long before I realized it lol I'll get going now, but these tips should help you make friends.
You can see the cosplay list for me in my signature under my post, but if you want to you can PM me for pictures of my cosplays. I am telling you this because I am inviting you to feel free to talk to me and hang out with me if you want to do so.