[objplant]

I would suggest not to join a hobby, interest group etc. with an agenda of making friends. I think such a plan might create some unnecessary mental pressure on one's behaviour. On the other hand if you join a group with a topic that really interests you, chances are you'll be sorrounded with at least some like-minded people. And then, if you casually fall into a conversation with someone, then you grab the opportunity for making an acquaintance. And that person might some day turn into a friend.