[Sangetsu]

Don't stress the details, Japanese assume all western foreigners to be ignorant of Japanese manners or Japanese language. You won't be thought of as stupid or ignorant, you'll just be thought of as a foreigner, which is, in fact, what you are.

To get around in Japan, you need only know a few phrases (good morning, good day, good evening, sorry/excuse me, and thank you) and you should be able to read a map. Print out maps in your own language, they'll come in very handy during your visit.

You'll find almost all signs at train stations to be bilingual in Japanese and English, and most announcements will also be made in both languages. Most ATM machines are also bilingual, and the majority of Japanese (whether they'll admit to it or not) know at least a few words and phrases in English.

Currency exchanges are always multi-lingual. Your best bet is to exchange your money in your home country before you leave. Otherwise, you can exchange it at the airport (the airport in your own country, prior to leaving, or at whichever airport you arrive at in Japan).