Don't use AF, you ideally should take a direct flight as the flight duration is around 11 hours. BA flies direct without any changes.
Taxis in Tokyo are hideously expensive to use so avoid. We used a coach transfer from Narita into Tokyo.
Price of food, let alone fruit and veg in dept stores can also be astronomical compared to what you see here. Gifts of peaches in boxes and melons on sale for £100 are not uncommon. Lots and lots of chocolate and french patisserie for sale too in stores basement. Fruit jelly on sale is wonderful to eat. More western style restuarants like TGI Fridays (menu is in English but again staff do not speak much English) and McDs are in Ueno. McDs are popular in Tokyo and service is very quick. Menu is also in English. Hard Rock Cafe and Tony Romas are located in Roppongi which is generally a more westernised area of Tokyo.
Japanese service is wonderful and cashier will bow when you make a purchase. It will be wrapped as well after you buy an item, no just chucking it into a plastic bag!. Japanese made rice bowls and chopsticks are a good buy, clothes there are generally not made to fit Western figures. Everything clothes wise is teeny tiny!.
English is widely spoken in hotels generally speaking.
July may well be hot and humid especially on sunny days. Use a fan and wear smart casual clothes. Some Japanese put a towel around their neck to soak up any sweat. Jeans and t-shirt combo does not quite cut it in Tokyo; its a very style conscious smart city and you can sweat like buckets when the humidity is high.
Toilets in hotel rooms have push buttons on them; the most unusual one I used played a tune (this is to disguise the noise of the flush!).
You will see the ubiquitous drink vending machines in stations and in the streets and none are damaged.
At present Tokyo metro does not run air con everywhere on its metro network and walking between stations underground can take some considerable time particularly if you use Tokyo station. Ensure you have a map detailing the number of each metro exit; using the wrong exit at a station can easily put you half a mile out of your way!. Also avoid using the Metro system in the morning rush hours (after 10.00am you should be okay); it makes the London Underground tube here look sedate by comparison!.
Japan is a very seismically active country but they are truly the most prepared in terms of earthquakes.
Would I go back - oh yes most definately.