This is such a BIG topic and one I will be doing much more on in the future. My general advice for beginners or those who have NEVER performed in front of anyone before is this. Play WITH other guitarists and musicians before you play in front of any audience.
Confidence and self belief comes from successfully DOING the thing again and again until your PROVE to YOURSELF that there is nothing to be nervous about. Go through this process with others in a group is much less painful than going it alone, and the experience is SO valuable no matter what you go on to do on guitar.
Playing with other musicians will give you many advantages including (but not limited to);
A sense of camaraderie with your fellow musicians that will help you get through
Experience playing 'in front of' other people, but those other people are playing music too!
Support from the other musicians to help you if you struggle at any point
Safety in numbers is so, SO true when it comes to performing. Even now, for me playing alone is always so much more intense than playing with a band, and playing in a band or just with other musicians is nearly always more fun!
For your first performances, take the heat off yourself and get used to playing with other musicians before going it alone.
I will speak more on this topic in the near future. Thanks for listening!
