Do not center carpet. A carpet must always be centered on something. While many people simply use it in middle of room, this is not always best technique. If you have a round area rug on carpet, you have to center it with a ceiling light. Regarding small rectangular mats, they must be centered with a doorway or hallway. In office, carpet should focus on desktop in room with couch.
Do not try other ideas in room. Room is a common area rug on carpet, but many people tend to arrange them same way. Try other techniques that can make space look more interesting. For example, use a large rug, and put it under a bed side, so that extends to one side of room. Also consider using a small rug that is same width of bed, and put it in front of bed. Choose a striking pattern to give interest to decor.
Put carpet away from wall, or very close. As a rule of area rug on carpet, a carpet must be no more than two feet from wall, and no closer than six inches. Thus, carpet may supplement space, and not draw attention in a negative way.