Furniture should be placed in a way that does not restrict free passage through the room. People should be able to sit with their backs to a wall whenever possible. One famous Feng Shui principle is the positioning of the bed. It should be positioned in way that you can see the door from the bed, but never positioned in a way that it directly faces the door. The bed must also be placed against a solid wall, and never under a window or beside the door.
via Home Adore