As with every kind of relationship, the foundation of being a good roommate is communication. The trade-off that is made between living with others and living alone is that you do not get the same kinds of freedoms, and you have to let people know if there is going to be a change in circumstances that will affect the experience of shared living.
One of the most common issues that arises with this is the problem of having guests. On the one hand, it is important to accept that when you have roommates, they may have friends and romantic partners visiting the house now and then. On the other hand, everybody who lives there should know about this, and these visitors should not be overstaying their welcome. It is no surprise that visitors can be a common source of tension between roommates, especially when they are not told about them in advance.