Basically, be your yourself. Try and communicate with the audience but there's no need to say too much and don't try to be a comedian especially if you're not one.

Until you are more established and confident, I'd suggest dropping in one or two traditional and/or covers alongside your own material. If your own music is good enough, it will take over eventually I'm sure.

If you don't compose your own stuff, that's quite OK, although I wouldn't rely on just the well worn standards etc. Look for something more original and different too. Again, until people get to know you, I think a mix is best. Unless, you are already outstanding in your own right, of course.