I like Ruth's answer. I usually just say "wish me luck." If you want to wish good luck upon other people, you can simply say "good luck" like Ruth said or "best of luck." Another phrase (typically used before someone does a performance, like acting in a play or doing a musical performance) is "break a leg!" which means "good luck" or "do a great job."

I agree with Ruth and Lauren. But I would also add that not only is it important to know if something is used, but also when it is appropriate to use it. In other words, if you over use it or use it in unexpected situations, it might sounds very strange.

Hi Julia, Usually we say: 1. Wish me luck! or 2. Good luck!

Yes. People commonly say this when they are about to do something important such as taking an important exam, going for a job interview or putting on a performance. They may say to someone, "Wish me luck!" or "Wish me good luck!" and the person will respond, "Good luck!"