I'm very superstitious - much to DH's chagrin
Knock on wood
Salt over shoulder
Never walk under a ladder
Never cross the path of a black cat
If a knife falls on the floor you'll have company
If your nose itches you'll have a fight
If your right hand itches you'll get money; left hand itches you'll lose money
Never open an umbrella indoors
If your ears are ringing someone is talking about you
Never put shoes on a table or you'll have a fight
Your purse on the floor means you'll lose money
Don't buy yourself opals, opals should only be received as a gift or it's bad luck
Breaking a mirror brings 7 years bad luck
. . . those are the ones I can think of right now . . .