I've had a lot of what you're describing, down to the exact events. What worked for me was no trick, just deciding to lean into social interaction more and more. When I needed to I would remind myself that more good than bad has come out of me putting myself I'm vulnerable positions, and that "no one really know what they're doing", and we're all socially awkward and trying not to be.

It gets easier - think of the hockey stick curve. Nothing happens for a while, then it seems like it's all happening at once. At this point I have what I'd describe as short-cut mechanisms in my head - where at one point I'd have to talk to myself and convince myself that taking that meeting or saying hi was a good thing with tons of reasons, these days it shortcuts to "just do it" because I've had that conversation with myself so many times. What it's resulted in is me actually responding right away to things, being more open to social interaction, and I'll wholeheartedly say I was right - it's led to more good things than bad, every time.

Hope this helps!