How to ride the Shinkansen if you don't speak Japanese

It might seem daunting going to Japan without knowing any Japanese and wanting to ride the trains without knowing what is going on. Here is a simple guide.
Firstly, the ticket staff will usually know at least very basic English words like ticket, pass, today, tomorrow etc. If you can, try and get some romanji or Japanese words printed out onto paper in your pocket (or take a phrase book) to make your life easier - they also might have a member of staff who's English is better.
If you want to get the standard all-Japan rail pass, you MUST buy it outside of Japan. It gives some good deals on train rides for a fixed price but note that you CANNOT use it on the Nozomi Shinkansen (the fastest one), probably because it is the most crowded. The Hikari - the next fastest - is not a great deal slower so don't cry about it.
I didn't buy the Japan rail pass but a JR West Sanyo area pass. This is a 4 or 8 day pass for all JR trains from Osaka in the east to Hakata in the west for 20,000 Yen - £160 - $250 (4 days) and 30,000 Yen - £240 - $375 (8 days). To buy it, you need to go to a JR ticket office or selected travel agents. Most stations seem to be brimming with ticket offices so you won't have a problem finding one, I went to the one in the subway level of Shin-Osaka station (this is the only place where the Shinkansen stop in Osaka). You will need your passport to prove you are a foreigner. Theoretically you will also need your exit plane ticket to prove you are leaving but I wasn't asked for this. Make sure you tell them when you want it to start otherwise they might start it too soon and waste some money. It only took a minute so you won't need to get it in advance (although there might be a queue when you go so I wouldn't advise cutting it too fine).
Once you have your pass, you can either simply get on the train to somewhere (travelling in the unreserved seats coaches - look on the information screens) or otherwise go to a JR ticket office that is displaying a green person sitting on a seat and you can get a free reservation to go with the pass. Note that you will need to know the services you need the reservations for (they are labelled with a service number rather than a time but you should be fine if you know it is the 9 o'clock to Hiroshima).
The displays are shown in alternate Japanese and English, they will show the type of train (Nozomi, Hikari, Kodama in the case of Osaka) displayed in a certain colour to make it easier to find, the number of coaches it has to help you find your coach with the platform markings and the coaches which contain the unreserved seats if you do not have a reservation. Note the platform numbers follow a hotel style with the first number being the level and the second being the platform, the lowest therefore would be 11 and others on the same level would be 12,13,14 etc. Most stations only have up to about 4 or 5 platforms.
The trains are often 16 coaches which is very long. At busy times, you do NOT want to try and walk down the inside of the coaches and you will not have time to walk along the platform, most services are in the station for no more than 1 or 2 minutes and 16 coaches is very long. Use the markings on the platform to find your coach before the train arrives. You might notice some white lane markings on the platform. This enables queuing of people on the platform (rather than pushing in) and also keeps them away from the doors to make space for people coming off.
If you do not have a reservation, do not be surprised if you have to stand in the aisle. Most people stand all the way up the coach to try and grab the seats when they become vacant. Make sure you are ready to leave the train as it arrives at the station, you will not be popular pushing past the people getting on because you weren't paying attention, you might not even make it to the exit before the train leaves!