Lots of good advice here... I moved to a new city/state in 2014 and I've made a ton of friends/acquaintances. When I was younger (even in university) I had a terrible time making friends, I was shy and had social anxiety. I really had to consciously try to be a different person - more outgoing, more friendly, less self-centered, etc. It helps a lot to come up with a specific, social hobby that you genuinely love - not something generic like going to the gym or being at work, but something that helps you find "your people," whether it's a science fiction book club or Alpine climbing. If you have no non-generic interests, now would be a great time to explore :-) And it helps to be the person with a plan. When everyone else is sitting around wishing they had something to do this weekend besides watching TV, you can be the person with an interesting thing to suggest. That's what happens in my office - someone says "what's everyone doing this weekend" on Friday or "what did everyone do this weekend" on Monday and everyone's like "eh, not much" until I rattle off a great story about something cool I did. People will want to hang with you if you're always up to something interesting and not just another drone.
Talk to everyone. Be friendly and ask questions. You don't have to be brilliant, just ask them about their weekend or the weather or their dog or their shoes. Don't limit age or gender or "type" of person. You don't have to be best friends with everyone. But just practice talking to people and you never know when you'll click with someone. I literally have made friends from age 20-something to 70-something since I moved here. Men and women. Rich and poor and in between. Bartenders, scientists, artists, laborers, CEOs. It's nice having a big range of friends, I have someone to go to bars with and someone to go to the symphony with, someone who will go to just about anything if it's free, etc.. I talk to people at the bus stop, I talk to cashiers at the store, I talk to the person next to me in line, I talk to the person sitting next to me at an event, etc. etc. It doesn't always spark a long conversation, but it still is nice to have a friendly exchange with someone. Maybe only 1 in 25 turns into a long-term friend/acquaintance, but if you talk to people every chance you get, that's a pretty good number.
I try to bring value to other people's lives. Give people a reason to want to be your friend! If you manage to make an acquaintance, do little nice things - give them tips about fun things happening or a great sale at the grocery store or warn them about a traffic problem or whatever is relevant to your lives. Be proactive about being friendly. Organize things - hey, I'm going to the movies, does anyone want to join me? Hey, I'm going shopping at [store], does anyone want a ride? Hey, I'm going for a hike, does anyone want to come? Hey, I'm going to see this great band, does anyone want to join me? Hey, I read this amazing book, would you like to borrow it? Be the person that makes other people's lives a little better, in whatever ways make sense for you. Unsurprisingly, more people want to be friends with someone who makes their life interesting/better/easier/more fun. When they are bored and want to do something, they will think of you instead of that friend they already have who doesn't do anything except talk about their toddler and watch football on TV.