… Leave a place BETTER than you found it. (Pick up trash, sweep the floor, arrange the throw pillows nicely… Whatever you can do to show you care.)
… Return borrowed items PROMPTLY, and in top-notch condition.
… Treat other people’s houses and property BETTER and with MORE respect even than your own. (Just because you don’t care about wearing shoes in the house, does not mean they don’t care. Just because your couch has had lots of little dirty feet on it does not mean theirs has, etc.)