For me that means meeting people via activities. I’ve additionally found I’m happier when I’m a bit active so a lot of the specific examples lean that way but the general principle is the same.
Structured activities where the whole group is 20 people or less I can almost always handle especially if the activity itself is solo and the group socialization part can be dropped into and out of easily. My favorite activities like this are target shooting or archery: can’t handle people for a bit? Go shoot targets no one will disturb you. Feel like interacting? take a break and go to the water cooler ask for a tip on your form, compliment someones grouping etc and a conversation naturally starts up. But as soon as you are getting overstimulated it’s easy to go “I should really go practice see you in a few rounds” and drop out of the conversation.
Classes where we have to partner up so I’m interacting with a person or several people within the class, but one on one, with a known end time, work really really well for me. On days I can handle more interaction the door to chat a little during class and usually there is some conversation that happens just after. On days I don’t feel up to socializing there isn’t an obligation though. And because the interaction is structured around a skill I don’t ever have to stress out about carrying a conversation. For me boxing worked well, as did dance classes (which after I had done for a while so I felt comfortable and less like I was going to step on my partners feet led to social dancing). Language learning classes and meet ups were tougher but still worked well.
The final thing I did took some work but It’s really paid off in terms of expanding the people I know: I actively tried to turn myself into a social information hub. I have become a person who knows what is going on in my city in any given week. What are the beer festivals? What community events? What operas or plays in town? What fun runs are happening? What concerts are coming up? I don’t go to 95% of the things I know about but it means I can immediately make myself valuable to a new acquaintance by going “Hey you expressed an interest XYZ did you know $eventRelatedToActivity is happening? Seems like something you might be interested in” which firstly shows them I listened to them which everyone likes and makes them like you more and secondly tells them I’m a good person to maintain contact with because I can point them to things they enjoy.