How do you adults socialize?

Hi guys, I recently turned 18 and am learning a lot of things Like how making friends isn't as simple as being put into a group assignment with them(in the classroom/college) So I took initiative and started looking for trends through video games, that way we'd have a common interest. But often times It turned out they were more indoorsy people and rarely found long term friends💔

And often times friends I made at tu actions felt more like business partners, sort of networking people ya get it?

Some tips I got from people I know is to walk up to people at cafes or places I usually hang out but I kind of can't (partially because of fear of rejection and not wanting to seem like a confrontational stranger)

What advice would you guys give, or how would you usually make friends?

Thank you for your time.

--don't let the header exclude you if you're not an adult, feel free to speak up if you feel you have anything to add!