6. Ignore the timetable
The biggest pet peeve staff at restaurants have is when someone does not respect the timetable. And for good reason! If they are preparing to open, it does not mean that you can go inside already, especially 30 minutes before the opening time.
The same goes for the people who come in 30 minutes before closing and they loiter around. You would hate it if you had been on your feet all day and are preparing to go home, only for a party of five to stay after closing time because they are chatting away. Respect the opening and closing times, make sure you do not stay behind too much. The staff are also people who want to get home and after you leave, they generally have to clean up as well, so make sure you are not that person.