Keep in mind the shape of the space where you will place the furniture. You wouldn’t want to place a curved sofa against a flat wall. However, that same curved sofa would look good placed in a corner of a bay window. If you’re placing a sectional in a square room, the L-shaped style will almost always look better than the curved sofa. Flat wall = straight furniture. The same goes for hanging wall art. Take into account the shape of the wall space where it will be hung. If it’s a rectangular area, typically a rectangular piece of art will work best. Do not place furniture off-center.
Imagine that your room is cut in half, from top to bottom and from side to side. That would create four quadrants. Now imagine that you are looking at the room from above. You want these four quadrants to have about the same amount of visual weight. If you have doors in any of these quadrants, you’re obviously not going to put furniture there. When you see the room in normal elevation, the door will be the visual weight in that area.
Don’t forget to measure. Don’t forget to measure the room. Draw it on graph paper before buying furniture. There are many websites online where you can do this as well. I usually start with Photoshop and create my mood boards. So I use Floorplanner.com to lay out the furniture. Measure twice, buy once!