Mazal tov
"buena suerte"
Удачи Udachi
When congratulating each other, or wishing each other "good luck", Yiddish speakers almost always opt for the Hebrew phrase pronounced "mah-ZAHL TOV".
Although there are a few spells used to bring good luck it is more common to make and/or carry a talisman or amulet for the purpose. Amulets are usually items such as jewelery or something already...