[Columbine]

You could always get a suica card or pasmo card too. You can buy one at the machines where they sell regular tickets- it's something like 200 yen for the card and then you can charge it and use it to hop on hop off without buying a ticket every time you want to travel so it's pretty convenient.

Trains are usually well signed, and theres plenty of English around. If you're studying Japanese I'd brush up your numbers (for finding platforms and exits!) and how to ask 'is this train going to XYZ', 'where's the station?' and 'I want to go to ABC, which exit should I use'. Plus relevant vocab to understand the answers. BIG big stations like Tokyo, Ueno (I think) Akihabara etc have little tourist info booths in them with english maps with points of local interest marked on them.

But don't forget, sometimes getting a little bit lost and just wandering can be fun as well! Close your map and get off the beaten path a little from time to time, you can find some great stuff most tourists miss, and there are stations everywhere so you can easily find your way back again after.