How do you break bad luck?

The answer depends on the type of bad luck and how you supposedly got it.

Spilled salt - throw a pinch of it over your left shoulder.

Put your shirt (or over article of clothing) on backward/inside out - remove the shirt, climb back in bed, get up again and put on a different shirt.

Passing a graveyard - cross you fingers or hold your breath until you are past.

Black cat crosses your path - cross your fingers, spit on the ground, turn around and go another route to your destination.

Crow (or raven) flies across your path - recite the "Lord's Prayer" while the bird is in flight and in sight.

General "bad luck" from unknown source - carry a "lucky" charm, amulet or talisman.

Bad gambling luck, from unknown source - stand up from your seat, move your self to another place/table, move your money/chips to your other pocket/side. Or go home and try another day.