I've been getting a lot of questions lately about sushi. Most of which have revolved around the terminology and how some of the condiments should be used. So, let's start with a few definitions.
Sushi refers to anything that is served over vinegar rice (rice seasoned with rice wine vinegar). It has nothing to do with raw fish. If vegetables, cooked meat, cooked seafood, and/or cooked eggs are served over cooked vinegar rice, it is still sushi.
Maki are the rolls that most people envision when they think of sushi. To make Maki, a wrapper (nori or seaweed paper, thinly sliced vegetables or fish, etc) is spread with vinegar rice, topped with certain fillings (tuna, avocado, crab, cucumber, salmon, etc) depending on the type of roll, then rolled into a cylinder, sliced into coins, and served.
Temaki are very similar to Maki. They only differ in that Temaki are rolled into a cone shape and are meant to be eaten by hand (kind of like a wrap sandwich).
Sashimi is thinly sliced raw fish. It can be served as is with various sauces and just called Sashimi or served on top of an oval rice patty (un-vinegared), in which case it would be called Sashimi Nigiri. If the Sashimi is served over vinegar rice, it is Sashimi Sushi.
Traditional condiments are soy sauce, wasabi paste, and pickled ginger. The soy and wasabi are meant to be compliments. Soaking your "sushi" in soy sauce is considered bad form and will probably tick off the sushi chef if he catches you. Wasabi is a spicy Japanese horseradish that is turned into a paste to add a little kick. Use it sparingly. If you are not use to it, a very small amount is enough to clean out your sinuses and give you a headache for the night. The pickled ginger is to refresh the palate in between bites. It is especially useful if you are sampling a few different varieties.
You now know how to order and what to expect at a Sushi Restaurant. You also know how to properly use your condiments. You are a Sushi neophyte no more!
P.S. Japanese custom is to drink your Sake before dinner not after or during.