The best advice I ever heard was from an Irish friend that I used to play with. He had been in a band when he was in his teens that got a gig supporting a major Irish folk group of the time. One of the old hands noticed he was nervous and took him to the edge of the stage and pulled back the curtain a little. 'You see them out there' he said, pointing at the audience 'they know f*** all.'

It's great advice when you are wondering whether you can remember words/ arrnagements/chords etc. Audiences are much more forgiving than you think as long as you pretend to have confidence.