Another way to achieve balance is to choose furniture that matches in visual weight. For example, you wouldn't want to pair a comfy overstuffed couch with a spindly-legged coffee table. Instead, you should opt for a chunky coffee table that proportionally matches the girth of the sofa.
The scale of the furniture should work in tandem with the size of the room. If you have a small bedroom, you don't want to stuff it with a king-sized bed and matching dressers. It will make the room seem overcrowded and anything but an inviting place to lay your head. Conversely, if you have a cavernous dining room, a table for four and a small buffet will get lost in the vastness. As much as your furniture needs to have a sense of scale, it also needs to work well in the room.