I read about a book awhile ago about confidence here simplify it in the three Cs of confidence
Comfort in the environment - eg a guy getting comfortable and start treating the place like he does in his own house. He sits and stands comfortably in a low-energy, chilled-out way or genuinely enjoy the music and move around without caring what others think or being too much “in his head”. Those are the only two modes of behaviour in the club. Nothing in between will look comfortable. If you are trying to look like you enjoy the music by tapping a foot out of rhythm or nodding your head because you think you should you won’t look right
Comfort in Interacting with People- eg Guys that own model agencies, work in strip clubs, or manage a restaurant with hot waitresses get laid. One of the major reasons is that they are desensitised to interacting with beautiful women and so are comfortable around them. Someone who has worked for a model agency for 2 years will not be shaking, sweating, breaking eye contact, or otherwise looking nervous and uncomfortable if he meets another beautiful woman. She will unconsciously or consciously know that her beauty doesn’t phase him and this will mean he isn’t viewed as a lower life form like the other guys that obviously are very affected by her looks.
Corfort in your own Skin - eg A guy who consistently gets with hot girls, and is comfortable with who he is will be un-reactive and unemotional in the face of tests. People are shy because they are worried about exposing their weaknesses to others. They are scared of being seen as ugly, having a silly voice, being poor, or whatever else. So they say less and do less so that they aren’t found out. Someone that is content will not be shy to put themselves out there and won’t react as much if you test them.