Here’s a part of a very large article that I want to quote/retain for future use:
A guide to sushi etiquette
Getting a sushi chef to give you the best possible experience is largely a matter of letting him know that you’re serious, curious and respectful of tradition. So how to do this? Here are some clues:
DO call ahead of time to make a reservation, or at least to tell the sushi chef you’re coming. Mention you’d like omakase or you’d like to try some traditional fish or Japanese dishes.
DON’T go to a sushi bar on Sundays; the fish market is closed and the fish won’t be as fresh.
DO keep the towel you washed your hands on, if you eat sushi with your fingers. Generally you will receive a wooden “rest” for your towel. Fold the towel neatly and use that to wipe your hands on throughout the meal. Return the towel to the server if you eat sushi with chopsticks.
DO introduce yourself to the sushi chef. Tell him what you’re looking for in your meal (i.e., to try something you’ve never tried before).
DO tell the sushi chef what you like rather than emphasizing what you don’t like.
DO mention if someone referred you, especially if they’re a restaurant regular.
DO say you’d like to try something authentic. If you say “unusual,” you may get something with cream cheese.
DO look around and ask about dishes or fish that interest you.
DON’T fill the shoyu bowl with soy sauce. Pour in about a dime’s worth.
DON’T put wasabi in the bowl with the shoyu. A good sushi chef will put the amount of wasabi on each piece of sushi that he believes is appropriate for that fish. For sashimi, put a dab of wasabi directly on the fish. Use more wasabi for fattier fish, such as toro or yellowtail, less wasabi on lean cuts, such as clam or squid.
DO order sashimi first, then sushi.
DON’T pick up sashimi with your fingers; use chopsticks.
DO eat sushi with your hands or your chopsticks, whichever you prefer.
DON’T dip your sashimi in shoyu if the sushi chef has already sauced it. If in doubt, ask.
DON’T dip the rice part of the sushi in shoyu, just a corner of the fish.
DO eat a piece of sushi or sashimi in one bite. If it’s too big, ask the sushi chef to cut it for you, or to make the next pieces smaller.
DON’T put pickled ginger on a piece of fish.
DO offer to buy the sushi chef a beer or sake. “It makes a good bribe,” says Nao Saba, general manager of Mori Sushi.
DON’T ask for a California Roll. It’s a dead giveaway that you’re a neophyte.
DO ask questions about the fish — where is it from, what part of the fish is that cut from, etc.
DO use Japanese words for fish if you know them.
DON’T order all the sushi you want at once. Sushi should be eaten right after it leaves the palm of the chef’s hand.
DO finish your meal with tamago (egg custard), vegetable maki (cut rolls), such as cucumber roll or oshinko roll (sour plum with cucumber and shiso).
DO eat around. You may need to try a few places before you find a sushi bar and chef you like.
DO go back once you find a sushi bar you like. The experiences that follow promise to be even better than the first.