Eating raw sliced garlic mixed with yoghurt is believed to bring you good luck. We're not sure this would have the desired effect if taken before a first date though. It's also thought to be a powerful cold remedy - which makes more sense, as garlic is believed to stimulate the immune system.
However, telling someone about your dreams before you drink a glass of water is believed to bring bad luck.
Austrians tend to be modest about how successful they are, especially when it comes to money. Perhaps this is because it's traditionally thought to be bad luck to mention how successful you are - and if you are stupid enough to mention it, knock on wood to make sure you don't lose that good fortune.