How to build this up? Please Answer?

How do you build up Self Confidence like letting go of what people think about you. I also want to build persistence. You know what I mean? Like if I get knocked down, I get up, almost stubborn. I want to be able to truly mean what I say when I say "I don't give a f*ck what you think, say, or do." Almost like Hed P.E's song Wake Up.