I have debated (inside my head only!) whether to sit facing the audience, or give them visibility to what I'm doing. Since I don't sing, I have opted to either face away from them (as an organist would) or angle myself ~45 degrees so I don't seem as if I'm looking at a wall.

I find that many times people seem to enjoy coming up to watch what I'm doing. I simply turn toward the audience when I'm going to speak, announce a song, do a dedication, etc.

Jim