[ChisaChi]

If you just want to learn a few things quickly for a holiday then basic words and phrases you're likely to need in the situations you'll be in (like yes, no, please, thankyou, where is ____, do you have ____, I'd like to order a ____, names of food, numbers) might be more useful than getting too heavily into grammar. But if you really want to study Japanese for more than a holiday then maybe look into doing some classes? It helps so much to have a teacher, I think.