[Dromar]

I'm pretty similar to you I guess.

I wear regular clothes, no sunglasses, no hood or anything.
No mp3 player.
I just use a table chip to protect my cards.
I try not to take bathroom breaks very often. I think it disturbs my flow. If I have to to, I'll take a 10 or 15 minute break, and usually play for 4 hours or so before I take another.
I don't drink anything while I play, except maybe I'll get a water a few hours in.
I make small talk and try to get everyone at the table talking and laughing. I never talk strategy or anything like that. IMO, getting the table talking is tremendously profitable.
I always pay attention. I also always show my bluffs that got called on the river, and act like I might win the pot (I play LHE). "Ten high."
I also always congratulate people who beat me in a pot, no matter how they played. "Nice hand." "Well played." "Good bet."