One of the things I brought back from Japan was a shoes-off sign for my bedroom door.
The sign has a picture of some shoes in a crossed circle. The writing is in Japanese. It says 'wearing shoes in here is prohibited.'
Of course, it is my parents house, so if they want to come in my room with shoes on, I cannot stop them.
If I had any friends visit, I would ask them not to wear shoes in my bedroom. However, I do not entertain visitors often and when I do, they seldom enter my bedroom.