When you are invited to a restaurant, you do not want your host to spend too much money and you do not want to act as if he can only afford the cheapest meal. Therefore, if there is a complete dinner (table d’hote), feel free to order an entree from the medium price range. If you choose to order à la carte, skip the appetizers and soup, and just order a salad, entree and dessert. If your host recommends soup, then it is acceptable to order that as well.
Before the waiter comes to take the orders, you might ask the host or hostess, “What do you think you will have?” If it sounds appealing, you can say, “That sounds delicious. I think I’ll have that, too.” But do not feel under the traditional Japanese compunction to have exactly what everyone else is having. That is not a part of American culture.