There are tons of different ways to translate that, so actually there might be no wrong or right. I'm gonna do my best to give you a natural way of saying it. やりたいことをし続ければいつかいいチャンスが来るかもしれませんから決して諦めないで頑張ってください。 Romaji: Yaritai koto wo shitsutzukereba itsuka ii chansu ga kuru kamoshiremasenn kara kesshite akiramenaide ganbatte kudasai. Basically, it's what you said. "If you continue doing things you want to do someday a (good) chance will come along so never give up and keep doing your best!" As I said, this is just one of possibly 1000 ways to express what you wanted to say. But I'm pretty sure that this is a natural and friendly way to say it. Hope it helps.