Well... here's the problem with lacquer, its not metal. Metal can be polished, lacquer can be rubbed with special clothes and polishes until you pass out from exhaustion and you won't have accomplished anything. Lacquered horns can be cleaned and maintained but not polished.
I would regularly wipe it done with a soft cloth (to remove dirt, oil, debris, sweat, spit, etc..) and pull a swab through the bore (I like padsavers although some people don't). Some people also apply a thin coating of Runyon Lacquer Life or Pledge to the finish. I have no idea if that works but it makes sense that it would (sort of).
Aside from that though, there is nothing really that you can do. Besides, playing wear (scratches, worn spots on touch points) never hurt anybody.