Been there done that. Want to do it again. When large amount of money spontaneously appears.
General (tokyo):
It's very very humid. It's hot, but the humidity is smothering. Also, people grow lawns on top of office blocks.
Your hotel room will be the size of three cupboards. One of them being the bathroom.
Everything is expensive.
Everything is designed with Japanese height in mind.
The only distinction between where tokyo ends and the surrounding cities begin are that people begin growing crops on the roofs of their houses.
Watch out for the bullet trains, a return ticket on them between cities is like $500. Buy a year pass.
There are often large market car-boot fairs held. Instead of junk however you can pick up clothes, computer parts, anime merchandise that would cost $120 here for only $10, etc. You need an actual Japanese person over there to find them for you.
It's far more crowded than somewhere like NZ (similar country size, 3% of its population size), hence getting smoshed in train carridges, endless queing, and generally insect like bustling that can be quite overwhealming is to be expected.
To find someone with purple, blue, etc hair you have to go out into Harajuku after dark. Watch out for people in bright green with soft toys stapled to their clothing. They hunt in packs.
The length of school uniform skirts depicted in anime is infact not a perverted exageration. They are that short. I pity the girls walking up stairs.
Once you leave the immediate vicinity of a major train station or airport, the signposting will be with English, but it will soon run out as will the people that understand your confused questions.
Nobody seems to walk between the districts (Akihabara, Ueno, Shinjuku, etc). They all seem to take the trains or subway.
Taxi rides can be similar to 007 movies.
Of course there are the vending machines. As opposed to New Zealand with a dairy on every corner, in Japan they have a vending machine on every corner. And every side street. Alleyway. etc. Everywhere. No two vending machines are identical and so do not expect to be able to get the same drink twice. Except for Canada Dry Ginger ale. Good stuff. Also, try not to drink anything odd looking from them, it's probably some freakish snake oil cocktail for business workers that need a buzz after their long 2 hours sleep. Also, there is no security to stop you buying whatevers in it be it alcohol, cigs, adult material, etc, they are also not chained down. Japanese society works. Nobody will steal them.
I did not find any pantie vending machines.
Akihabara (tokyo) is the only place you need to go.
Akihabara:- On Sundays they close off the main road to turn the street into a big plaza where bands come out to play
- There are alot of tiny stores which have a really tiny area space, yet have five floors of similar space.
- Almost everything is 5-6 stories high.
- Wear glasses and smile. Don't show fear as you are irasshaimase'd to death by thousands of store clerks. Applies anywhere.
- Appearances are deceptive, if you see a shop that appears to be selling electrical components out front, that's the one with the katars, swords, knives, and miniguns.
- Again, appearances are deceptive. Anyone you think is a cosplayer is infact trying to sell you something. Any Samurai you see are infact trying to sell you dishwashers.
- There is no real distinction or warning (like signs or a bead curtain) as you enter an r18 section of DVDs, Manga, or toys. It just all gets slightly pinker. Don't bring fathers with you.
- Many of the 'westerners' there are Europeans.
- You may be able to buy anything you want there, but with media, you must remember it won't be subtitled, and probably wont work on an American or any foreign player or gaming machine. At least immediately.
- You could probably spend a week here.
- Bring limitless amounts of cash or you just want to sit down and cry at the fact that you are overwhealmed with choice and can't decide.
- Watch out for model kits, they are designed for crazed japanese people with crazed japanese skills.
Some of what I said is here:
http://cstephens.livejournal.com/46931.html#cutid1 along with other stuff from when I went to Japan last year.