For subways and local trains, you'll most likely have to buy your ticket from a machine. They're pretty easy to understand even if you can't read kanji as there is a diagram explaining the routes; from this you can find out what your fare should be. If you can't work the fare out, a solution is to buy a ticket for the lowest fare. When you finish your trip, go to the fare-adjustment machine (seisan-ki) or the staffed counter before you reach the exit gate and pay the difference. JR train stations and most subway stations have posted above the platform not only their names in kanji and romaji but also the names of the preceding and following stations.