Some of this will just be good ol' common sense and politeness.
Not all of these fall strictly under the category of "bridge ethics," but none of your opponents will like it if you:
1) Come to the table dressed like a bum.
2) Come to the table reeking of strong perfume or cigarette/cigar smoke.
3) Come to the table smelling like you never take showers.
4) Chew/pop gum.
5) Snap cards (or play them in any obnoxious way).
6) Delay the game