I’ve heard the advice to:
“Fake It Till You Make It.”
Shyness, Anxiety and Low Self-Esteem are all abstractions.
They are terms or labels that are applied to something specific.
Most people get shyness and introversion mixed up.
Here’s a clip from Susan Cain’s website.
Bill Gates is quiet and bookish, but apparently unfazed by others’ opinions of him: he’s an introvert, but not shy.