Some basics that I have learned: Audiences like songs more than instrumentals (unless you are playing to a room full of musicians and you really do have something to show). I limit instrumentals to one or two per set. It helps a lot to be comfortable (I know you have to have experience for this; I did) and to talk between songs. You have to communicate with the audience, but never (I hope this comes off the right way) forget that what you're doing, you're doing it for yourself. It doesn't mean nearly as much to your audience as it does to you. Performing, once you've got it in your heart, is a need, not a luxury. All good musical performance is also theater. You have to assume the "role" of a song. Otherwise they all sound the same, which can easily put off an audience.
Good luck, Chet W.