Japanese street fashion is famous around the world, especially for the Gothic Lolita style. If you're visiting Tokyo, a day out in Harajuku to people watch in some cafes is a great way to see the many different kinds of Gothic Lolita fashions worn by the Japanese.
Make-up is also important and it still amazes me how detailed some of the designs are that people paint on themselves. One great resource is La Carmina, herself a Japanese fashion lover with an interest in Gothic Lolita and many more. She also has some great guides on where to go in the city for the less well known stuff such as theme restaurants and punk style clubs.
Is this your business?