I will never own or run a bar, but if I did…
I would not have a TV set. Or if I did, I would turn it off unless what you were showing was also what you were listening to. A TV just draws your attention. It is very distracting. Every place I go to has TVs all around turned to some crap show or billiards tournament.
I would pay attention to accoustics. Not only the music, but try to cut down on echo and reverberation so people could talk to each other.
Other than that, I don’t know. One idea I had was to play classical music. Not quiet music, but loud Russian stuff.
What would you do?