If you stay in Japan for 2 weeks, you will miss western food.
Luckily Japan is not a place where you have to eat rice and fish. There are plenty of western style restaurants and cafes.
Then there are lot of places open from early morning to late evening. If you stay at hostel and want to have a breakfast, cafe restaurant can be a choice.
Japanese cafes are divided into two types. The first one is that you have to wait to be seated. The staff will guide you to the table and tap water will be provided. Of course tap water is free of charge. Then, if you are ready you might have to raise your hand or push a button. In case you order a tea, the staff will ask you if you would prefer with lemon or milk. Please note that no where serve fruit tea if the menu is written hot tea. Also green tea is not available at western style cafe.
When you want to pay your bill, you have to take your bill to the cashier and pay there.
The second type is fast food style. You have to queue at the cashier to order. Please note that paying by credit card is not so common at cafe and therefore having a cash with you is always recommended in Japan. This kind of cafe will not provide tap water if you do not ask for it.
Tipping is not necessary and there is no small box for tipping at the cashier either. Even saying "keep the change"is not common in Japan. Do not hesitate to receive a change even an 1 yen coin!