gotta say, the only reason it's easier as a kid is that you're forced to spend time with the same people repeatedly: school kids, your parents' friends' kids, neighbour kids... etc. and that's all you need to do now -- find a way to spend time with the same people over and over. that's the core of it. now, it could be clubs, classes, work, and so on -- and the more you enjoy what it is that brings that group of people together, the more you'll enjoy the company of those people (probably). bars aren't so good for that kind of thing unless they're like cheers, where the same people go to hang out all the time...

basically, there's no easy answer how to make friends in a new place, and there's no shortcut. you just have to find a set of people and see them a bunch.