What exactly to say when you are a waitress?

There's nothing wrong with what you're saying. Each time you say it, it's to a new person. It may feel like you say the same thing over and over, but to someone different each time. The only thing I can think of to add would be, "Is there anything else you'd like?" before you set down the check. Basically, smile, be polite and efficient, call older people ma'am and sir and don't call us by our first names. When I pay with a card, I really hate for a waiter the age of my grandchildren to say Thank you, Debby.