I always tell people to remember why you're performing in the first place. For most people it's to share the love of the music. And why are people there? Not to make fun but to enjoy the music you love. I always try to blur the line between audience and stage by making it as inclusive as possible. Involve your audience in the song, not just by singing with you but giving the song a good set up. What is it about? What is you relationship to the song? Things like that. But if you're not enjoying yourself your audience runs the risk of not enjoying themselves too.
Good luck and don't over think.
David