Just a few of the superstitions that are were observed in my family:
Don't sit down if you have a 13 for a meal - drag a 14th in off the street, or seat your guests at 2 or more separate tables.
It's bad luck to have lilacs or any white flowers in the house (attracts the faery folk).
Also peacock feathers in the house are a no-no.
A black cat walking towards you brings good luck - bad luck if the cat walks away from you.
Never buy a new broom or brush in May.
Never open an umbrella indoors.
Never place a hat on a bed.
Accidentally putting clothing inside out is good luck - but only if you continue to wear it until the time you'd normally remove it.
It's bad luck to put shoes on a table.
Sow parsley seeds on Good Friday and wear new clothes at Easter to attract good luck.
It's bad luck to refuse a kiss under the mistletoe at Christmas.
Never give a purse/wallet to a friend/relative without placing a few coins inside.
If you drop a glove it's good luck if someone else picks it up for you - but you must not thank them.
If giving a gift of knives ask the recipient for a coin before you hand them over otherwise your relationship will be severed.
Crossed knives on a table, in sink, in a drawer, signify a quarrel.
If you spill salt throw a pinch over your shoulder immediately (straight into the devil's eye).
Don't position a bed so that the sleeper's feet point towards the door.
It's bad luck to light 3 ciggies with one match (from the Crimean War - possibly related to Orthodox Russian Funeral Rite where 3 candles are lit from one taper).
From Australia: always keep a witch (figurine) in the kitchen.
And never walk under ladders!