When shooting a very small room, there are several things to remember.
First, take the photos at an angle as commented on by Dawn Shaffer.
Second, if you don't have a wide angle lens, get one. I like the Panasonic Lumix FX35.
And here is a tip I like personally: Take off the door. This is especially helpful in small bathrooms. The first photo below is taken with a wide angle lens with the door on. The second, with the door off. You can see the subtle, but important difference it makes. The room feels larger, less cramped. It takes only a few seconds to remove most doors and the sellers will be very impressed with the results.