1. Get roommates. Not for everyone, but moving in with two other people even though I could afford my own place made it really easy for me to jump into tgeir friend circles quickly.
2. Meetup.com, Eventbrite and similar sites. Just pick a couple of things you’re vaguely interested in (for me it was language exchanges, salsa dancing, board games, and startup meetups) and show up every week. Even if you’re shy, you’ll naturally start chatting to people after a couple of events.
3. When you meet a couple of people, make your own events and invite them. E.g. If you meet someone at an event who likes rock climbing send them a text the next day saying “Hey, I’m going to a new rock climbing gym on Wednesday, do you want to meet me there?” Once you invite people to a few things they‘ll start inviting you too.
Does all this take effort on your part? Yes. But its worth it. And you’ll get better. I was bad at this when I was in LA, but after working on these skills I built upba friend circle in Taipei (arguably harder because of language barriers) within a couple months. Good luck and don’t give up!