Floor Space - "It's a good thing," as Martha Stewart says. Most people have a tendency to fill up a space. They think if it is empty, then it's not finished. Well, that's not true with staging.
Set your room so you can see more floor space. Now that does not mean lining the furniture up against the wall. It also does not mean spreading it out so much that you can barely walk through to the next room. Arrange the furniture in groupings so that you maximize the amount of visual floor space. The more floor a buyer sees, the larger they feel the room is. The size of the room does not change but the perception of the size does - bigger is better in this instance.