Suggestions:

- Really experiment with public transit in a new place. In places with good taxi service, you can't get stranded, so it's reasonable to just yolo it and not do any route planning when taking the bus/tram/whatever. You'll often discover cool places and nice routes that way.

- Find the parks. People in cities do all sorts of cool things in parks that people with large houses and backyards only rarely do in public. There's something magical about being in a public space with thousands of people all having fun and living the best parts of their lives.

- Look for a public events calendar, check Meetup, and (if you are willing) Facebook. Lots of people means lots of things happening.

- Figure out how to do the things you love even if they seem foreign to the place you are. It's your chance to find amazing people who enjoy those things so much that they're willing to go against the local culture to do them.

- Oh, and if you can, go up the stairs and not an elevator. It's good exercise, gives you a sense of agency, and you'll feel awesome each time you reach your floor.