I know it's a silly RPer thing, but I try to pay some attention to how my characters look in game. For example, I still haven't gotten the Shave and a Haircut achievement on my Death Knight because I think he looks pretty cool and very much like he should as a character and I'm having a hard time changing it, even for an achievement.
Another thing I do as a result of this is do varied and esoteric quests to get gear that MIGHT look good on me conceivably. Some day. Possibly. My Hunter has a full set of black leather armor in case she ever has to, I don't know, join an RP night stealth strike force, I suppose, and a torch in case she needs to lead an angry mob or something. It's a little obsession.