Tokyo is the most confusing city in the world. The streets have neither names nor numbers. The numbers on buildings are not sequential. You will get lost. Don't worry about it. It's part of the experience. Ask for directions frequently. Draw yourself maps.
The little buildings on corners with cops sitting in them are koban-- police boxes. They exist to help lost people. Go in and ask for help. If the cop does not speak English, say, "[place] wa doko desu ka?" Try to get him to draw you a map. He will be happy to help you out.
Or ask strangers. They may not know where you are, but if they do, they will be sympathetic. At any given time, Tokyo has thousands of lost tourists wandering about in circles.
As a last resort, if you get really hopelessly lost, you may have to go to the nearest train or subway station and take it to a stop you're familiar with.
(From the Nippon 2007 site, reprinted from Rachel Manija Brown's accounts of travels in Japan.)
Looks like "Get lost" is not considered an insult in Japan [grin]