to
all of that.
My DD has found that with a group of academic hypergeeks-- that's really about all that they have in common, aside from a love for literature. They're just "smart" kids-- and they range in age from 13 to 18, they're homeschooled, privately schooled, publically schooled, etc. All are high schoolers.
They met one another because of a volunteer-run local effort at promoting (serious) writing among teens. A local YA author mentors them-- the core group has also developed an interest in RPG as a social activity, so they meet up at least a couple of times a week. They are
all otherwise kids who would live on the fringes socially-- some of them would literally have NO friends otherwise, or may have never had friends before now.
It's all about finding a shared interest and other people who like it, too. Less isolation = better confidence. It's global.
Another thing that has really helped is volunteering. This was very hard for a lot of years, because we don't have a faith community to act as the backbone for such things. But if you find a local agency that NEEDS volunteer help and is something that your DD is passionate about, she can build social relationships there, too. It's slow, but it works a lot better than the cruising/drinking/parking method of socialization. (And yes, I've seen that model of "teen activities" as well; grew up with it. Not good.)