Usually the best way to find new people is to get into an activity or hobby. Use meetup, or Facebook events, or other local event coordinating services to find activities or events you’re interested, go and chat with people, and if you hit it off with people after a few times seeing them, try to make a connection individually outside the group, like meeting up for coffee or a beer, etc.
The hard thing you’ll find as you age though, is there’s a finite amount of social attention people have with their lives, and as people age and establish their groups of friends, sometimes its hard to break into their circles as they’ve already kinda maxed out their in life social network. Sometimes they either aren’t really looking to add more friends, and include more people in their life, or just don’t think to invite you to events etc. Breaking though that, or finding people open to adding more to their social networks, can be hard as you age.