It was a combination of several deliberate and non-deliberate things for me:

1) Age: I don't think I can overstate how much of a difference this makes in terms of not just your own emotional maturity, but also that of the people around you. It was much harder for me in high school and early college than later in life. In my late 30s now, and my friends groups just have zero drama and are mutually supportive as best as we can be. Just waiting can make it better, slowly over time.

2) Dating (usually online) and suffering through a shit ton of rejections in my early 20s, but still doing it over and over, just to meet more and different kinds of people. It hurt a lot at first but eventually it got to the point where I could walk away and say "OK, thanks for the transparency and the fun dinner! Best of luck in your search". It always stings a little, but you get over it and hopefully learn a little from it.

3) Forcing myself to try new things, with new people, across many swaths of society. I line danced with wannabe cowboys (and some real ones), sat in on city council planning meetings, planted trees, volunteered at nonprofits, attended Navy environmental reviews, joined a Wiccan meetup, went salsa dancing at the Mexican restaurants, joined a swim club, went rock climbing, rode my bike to a naked campfire, work-traded at a yoga studio, worked at different jobs from coding to farming to trailbuilding, played D&D with friends, went to house parties, did karaoke sober, joined dinner groups and dance groups with older people, played video games with frat kids... all in a few years. (Didn't get much homework done, heh.) For contrast, in years past I also spent the better part of a year as a depressed and suicidal teenager, at home, with almost zero human contact. I had to put in very deliberate effort, not being a natural extrovert, very shy and with a poor command of spoken English at the time.

4) All of the above, combined, led me to the most important development: making and keeping awesome friends. I have only three friends who code, and dozens more from different walks of life. They added so much warmth and comfort and love and acceptance to my life, especially the women who I had platonic relationships with (it is possible! and yes feelings can happen, but you just deal with them maturely and fairly for both parties).

Eventually you meet enough people and spend enough time with them to learn the best, most liberating lesson of them all: You're just not that special :) And that's totally okay! We all have our hang ups and fuck ups, and have made our share of mistakes. Try to love and forgive and understand other points of view, put yourself in their shoes, etc. and eventually the rest just kinda fall into place. Eventually you start to realize that everyone else is equally, if not more, anxious about one or more things in their lives. Even people I once imagined were social butterflies had hangups I thought were really silly but seriously scared them. And as much as I've grown, there are still situations that would make me super anxious.

Now, most of the above only really applies if you're relatively within the norms (however you define them) of society. I have friends who are on the spectrum to various degrees, for example, and it's much harder for some of them. They also cope in other, non-social ways that don't work for me. I can't speak more to that because I haven't lived through it.

But in general, just facing your discomforts one by one, repeatedly, and trying to learn from each one. FEEL each one and accept it and grow from it. It's not easy, but do what you can, and it'll be worth it however far you get!