In the US, there are many types of restaurants. Fast food restaurants are very famous. You can find many McDonald's and Kentucky Fried Chicken restaurants. You look at a menu above the counter, and choose what you'd like to eat. You pay the person who serves you. You take your food and sit down or take it away. There's no need to leave a tip.
In a coffee shop you sit at the counter or at a table. You don't wait for the waitress to show you where to sit. She usually brings you coffee when you sit down. You tell her what you'd like to eat and she brings it to you. You must pay the money as you leave.
In a family restaurant the waitress shows you where to sit. Often the waitress tells you her name, but you don't need to tell her yours. If you leave over anything, your waitress gives you a bag to take your food home. You add an extra fifteen cents to the bill as a tip.
In top class restaurants, you need a reservation and you need to arrive on time. The waiter shows you where to sit. If you have wine, he may ask you to taste it. You can only refuse it if it tastes bad, not if you don't like it. When you get your bill, check it and then add several dollars to it as a tip for the waiter.