In my opinion, to be confident you need to realize and accept two key things.
It is okay to have some self hate. Society has been on this kick of "SELF LOVE. LOVE YO SELF. ALL OF IT KIDDOS!" without taking the time to point out that it is perfectly normal to hate parts of you. Everyone. Has. Self. Hate. Say it with me! Even the most beautiful and confident being you've ever met has moments of "Fuck, I hate so and so." It is normal to dislike your nose or socially awkward way of interacting with people. However, it's not good to let those take the front seat. You have to take what you love about yourself and stick those things right in the drivers seat to drive you as a person forward. You gotta take the parts you hate and stick them in the back seat, accepting them and letting the hate be there, but not letting it control you. (I know this is hard to do, which is why number should help a bit.)
For the most part, meeting humans is this entirely meaningless day to day experience for everyone. When I first meet people my mind doesn't decode their flaws because honestly my mind is too busy being engaged in conversation. Whether it's an important person at work, or a random friend of a friend, when I first meet them I am literally focused on what they're saying and not what their flaws are. That's how most humans are. It takes a truly mean person to meet someone and balance speaking to them and thinking about their flaws and immediately judging the person over them. Which essentially comes down to... nice people don't give a shit enough to mentally point out about what you're self conscious of, and mean people shouldn't be given any shits about what they think of your flaws.
When I realized those two things I started engaging more confidently with others in business settings, at social events and even quit thinking of what meaningless passerby's opinions of me would be.