"Shinjuku - No Shrinking Violet"
Tokyo has about the same population as New York City, but the comparison ends there. Tokyo (esp Shinjuku) is simultaneously more frenetic yet more civilized. Culture shock upon arrival is amplified by sensory overload. Nonetheless, the inquisitive traveler will find friendly locals, easy transit and a galaxy of sights, sounds, tastes and attractions.
Find a guide book. Learn some Japanese. That's all I can do to help you. Trying to describe Tokyo is like trying to describe the 20th century. There is too much stuffed into too little.