Harajuku is more or less the teenage fashion street in Tokyo. It's uniquely Japanese - you cant quite compare it to any other place in the world. This is a brief guide on what to wear in Harajuku.
Its best to go with a good friend. Then you can dress up like twins.
Of if you're with a several friends, dress like you belong in a group - not the Mafia kind, but the boy-band kind.
You cant go wrong with either black or white.
Accessorise! Hat or head gear, ties, long stockings, wooly boots, etc
The "school girl" look is in - and easier to go as twins too.
You don't have to be Japanese - fashion applies to foreigners too.
And if you're a couple - dress in matching clothes.
And if all else fails... just dress weirdly.
Doesn't matter what you wear - you can always get free hugs