Having surrogate older bothers (aka older friends) has been helpful for me because they've been through what I'm going through and are at a point where they've reflected enough and know what I should and shouldn't be caring about. Of course they can be emulated when you notice they're being really effective socially-speaking.
I'm not saying you can just "pick up older friends, bruh", but if you end up with a friend who's in the older brother/sister age range, take advantage (in a good way) because you can learn from them and they will almost always be happy to be a kind of role model for you.
Writing down a "post mortem" after attending significant social events has helped me quite a lot as well. It's always good to write down thoughts while they're fresh, connect some dots, and hopefully remember something you've learned the next time.
While there's something to be said about living in the moment, reflection is super important. It's easy to coast through life, have things happen to you, screw up, and then continue repeating similar patterns. Writing down any relevant ideas and reviewing them prevents valuable insight from going immediately down the toilet.
One more thing is to practice looking people in the eyes. I'm bad at this because when I get thinking in depth about a topic, my eyes start to wander. But when the other person is speaking I've gotten much better about keeping eye contact. Just going in public and practicing looking at random people in the eyes was a big help. Yeah, it's awkward, and maybe it makes some people uncomfortable. You're gonna have to get used to making some people uncomfortable if you want to have good social skills, ironically, because otherwise you'll be too concerned about how you're perceived to the point where you're not making anyone comfortable. Maybe you'll creep some people out, but some people will look you in the eyes and smile back at you.
Somehow overcoming the eye contact thing permeates a bit into the rest of your social skills. You have to have a certain level of confidence to do it properly and to not think twice about it, and many aspects of social skills just have to do with confidence.