Formal:
* 祝你好運 (juk nei ho man) - This literally translates to "wish you good fortune." This is the most common and formal way to say "good luck."
* 一路順風 (jat lo shun fung) - This literally means "smooth sailing all the way." It's used to wish someone a smooth journey, but it can also be used for general good luck.
Informal:
* 恭喜 (gung hei) - This literally means "congratulations," but it's often used to say "good luck" in casual settings.
* 加油 (gaa yau) - This literally means "add oil," and it's used to encourage someone to keep going.
* 好彩 (ho choi) - This literally means "good luck," but it's more colloquial and informal.
The best way to say "good luck" in Cantonese depends on the situation and your relationship with the person you're talking to.