What orientation should I place my rug as a bedroom centerpiece?

Honestly, it does depend on your preference, but it could depend on the layout of your room, but landscape is often the best way, to create the illusion of space. The entire bed frame should sit on the area rug. Choosing a rug that's too small for a large bedroom will throw the space off balance. Grab your measuring tape to get the right dimnsion and take the flooring of the room into account. Are you trying to hide a carpet or wood stain you don't care? If so, then you should choose a size that covers more surface area.