Once a wedding ring has been placed on the finger, it is considered bad luck to remove it.
117
Placing a hat on the bed is, apparently, bad luck. (South Carolina)
9
If you catch a falling leaf on the first day of autumn you will not catch a cold all winter.
394
It's bad luck to leave a house through a different door than the one used to come into it.
143
If one walks underneath an open ladder it is said to bring bad luck. Sometimes it is said that this can be undone by immediately walking backwards back underneath the ladder.
105
In some parts of England, rum is used to wash a baby's head for good luck.
71
When you speak of bad luck, it is said that one should always knock on wood. Also knocking when speaking of good luck apparently helps with having good luck. This is an old Celtic tradition related to belief of wood spirits.
208
It is bad luck to put new shoes on a bed (or a table) (comes from the tradition of dressing a corpse in new clothes and shoes and laying them out so everyone can give their respects) - (UK)
57