Check the local papers, Meetup, etc. for events and community groups to join. Take public transit (if possible) to get a feel for the layout. Look at a bunch of maps, read some news stories, look at brochures, etc. Walk around a lot, hit up some bars, board game nights, karaoke, etc., and try to make new friends. It can be a lot of fun if you're the curious/social type, or just can fake it enough :)
Walk the place as much as possible/reasonable, to get your bearings, find the smaller non-touristy places, etc.