I've never had stage fright, perhaps because I started young, before I knew any better.
My advice, prepare and practice until the piece(s) you are going to play are totally under your fingers. Then tell yourself that you know it, you know it well, and the people will like what you do.
They will like you, because you are doing something they can't do and can't even imagine how.
I've been a pro all my life. I've had big screw-ups on stage. Not often, but they are sure to happen sooner or later. I'll say something to the audience like, "This worked perfectly in practice" or "Did you ever have one of THOSE days" or "Damn it, I got my finger stuck under the G-String again" and laugh with the audience. Everybody makes mistakes and as long as you joke about it, they will be forgiving.
Insights and incites by Notes ♫