I feel like the quickest way to change a space with the least effort and most impact is to switch out the throw pillows that are scattered around on chairs and sofas. I like the idea of putting pillows together with no rhyme or reason just because they are fun and colorful. We have a brown leather sofa, so really anything works to decorate it. Above are some fun pillows I found of all price ranges.
You can find these pillows here.