I’m boarding a flight to Tokyo at the end of the month, will be there for around 10 days. What should I know about traveling Japan and how much Japanese should I know?

I was given a plane ticket to Japan as a birthday present. My flight leaves on the 30th. I've taken two semesters of Japanese in college beforehand and I own a copy of the first volume of Genki. I know Tokyo can be accodomating to English speakers, but I'm still a bit worried that I'll get lost or I won't be able to talk to people if I'm in a situation where I need to. I plan on teaching myself more Japanese in the coming weeks, not going to assume I'll master a whole language in a month of course but just enough to get by.

Any advice?