I belong to three guilds. Two good size and one really small.
I will say it's nearly impossible to actually get to know people you only see 2 hours a month. Join in the activities and you'll get to know people a little better.
As to cliques, groups of friends sit together and visit with each other. So would you. As soon as you get to know some of them you'll be included because they're not really cliques, just groups of friends.