[brimble]

Easier said than done, but I think the key is learning to (selectively!) not give a shit. It's crudely put, but is the gist of what a lot of self-help stuff is, including fancy-pants stuff like Stoicism.

The blocks are purely in your head. Bad interview? It'll be forgotten by everyone but you in a week or two, if even that long, unless we're talking something outlandishly catastrophic ("... and then his tie caught on fire!"). Awkward when talking to a stranger? They'll forget you existed by the morning.

One helpful exercise can be to think through the actual harm—not how you'll feel about it, but all external-to-you harm—from a worst-likely-case scenario. Interview when you already have a job? The harm approaches zero. Talking to a stranger? Ditto. The harm of those is almost entirely something you do to yourself.

One simple way to practice social skills is to play little games when things are extremely low-stakes. Like, "today I'm going to compliment a stranger on something", or (a tad more advanced) "today I'm going to find out what a stranger's favorite sports team is", or whatever. Really little efforts are all it (usually) takes to reduce social anxiety quite a bit, it's just that lots of people never even try that much.

As for interviews specifically, the usual advice is "do practice interviews until no longer anxious".