When I first came to Japan we didn't have fancy smartphones or googlemaps.

You should be able to find most major sites, train stations have huge maps of the areas near the exits. Police boxes (kobans) also have maps of the areas posted on the side of them as well.

If you really need to get somewhere specific, I recommend printing out the address and the name of the place in Japanese rather than a Romanized version, so you can show it to a regular person on the street if you get really lost. I wouldn't worry too much about the numbering system in Tokyo (I sure don't pay attention to it much and I live there!) Just study the maps ahead of time, navigate using streetsmarts and using main landmarks (train stations, sightseeing spots) as your point of reference.