How to get more confidence and higher self esteem?

For years now I've been just a nervous wreck in front of people
Im fed up of it
I have no confidence what so ever, extremeley low self esteem
When someone talks to me one on one or in a group, I feel like I go really bright red and sometimes I almost...

cry...
I know, its stupid
Reciting im beautiful or whatever in a mirror doesn't work. It just makes me more upset.
I dont look in mirrors often because I really dont want to
Help? :[

look, people talk about people ~Like OMG! What is He wearing?! It's like so ugly!!!~ But they don't really care. I know this by thinking about how I felt when I talked about someone like that. people just try to make you feel ashamed. They won't ever even think about that moment again! There's absolutely no reason to not be yourself. And think of it like this, there's always that someone who thinks your ugly, but there's always that someone who thinks you're the most gorgeous thing alive. everyone has different opinions. just be happy with who you are, and happy for what you look like cause there isn't a thing you can change Hope you feel better!! Good luck!

Just think about the good things about yourself, I'm sure there are tons!
Boys don't really care too much about appearance despite what they say to their friends.
Just be nice and outgoing and they'll love you!
Hope this helps.

Please answer my last question I need help !