I want to decorate. Where can I put the washbasin with mirror? For example, in what direction, can I put it next to the toilet door? What are the taboos?

No, don't point the indoor mirror at the door. Generally speaking, the bathroom door will be mapped to the entrance door more or less. It is the most reasonable to put it in the bathroom. In addition, if you put the washbasin in the hall, it will not have a good effect. Try to think about it. Personally, I think so.