When someone is self-conscious, they are very much focused on themselves and how they think they are coming across to others.
One possible tip for a method to stop worrying so much about how you’re coming across is this:
Occupy your mind with this thought:
“Whatever happens, I’m going to do my best to make the person I’m talking with feel accepted and loved.”
By shifting your focus from yourself, to the other person, you stop worrying so much about how you LOOK, and allow yourself to BE the kindest version of yourself. Your aim is now not to obssess about “appearing” to look like a nice person, but to BE kind and BE nice so that the other person feels good.
When other people feel good, accepted and loved in your presence, do you think they’ll remember that your shirt wasn’t ironed or some other trivial thing you may be self-conscious about? Or do you think they’ll remember “Hey, it felt so nice talking with that person – they were so nice! I really enjoyed chatting with them!”?