I used to play a pizza joint/bar. Like Mary said, people would listen, even if they didn't appear to be. I played what I liked (for four sets and low money, what else would you do?). If there was a celtofile in the crowd they would like what I did. If not, they liked the guitar playing. I looked at it as a paid rehearsal. When I teamed up with Margaret, we got turned down at the same place as "not squire material" (the place was called The Village Squire). We thought about putting that on our promo material.
   Later on, we did some St. Patrick's Day gigs where the owner hadn't listened to the demo. The paid rehearsal thing pays off sometimes.
   I did get someone commenting that I looked like (on stage)like I didn't care if the audience liked what I did or not. Which might not work to your advantage. I wound up getting a day job, and just playing gigs where they want to hear what I do. (Check out tradfolky1 on youtube). Good luck.