If they are scratches, throw some clear fingernail polish over them to seal them over. Other than that, look at the Lizard Skins line to keep the bike "looking like new" cosmetically. I use the headset seal and the chainstay protector. Also, make sure the bike stays clean after each ride and isn't thrown back into the garage soaking wet or covered in mud without a cleaning and re-lubing at least once in a while.
-Moab
Edit: I was typing this while bac posted. Follow his ideas and you're set regarding the finish.