Add assorted throw pillows in different colors to add splashes of color to your plain looking sofa.
Update an old sofa pillow by using pillow covers purchased from a thrift shop or discount stores.
Drape a velvet throw in color that matches the pillows and your sofa to add drama.
Buy and slip on a slip cover on your sofa. Change it with the season. This is cheaper than buying a new sofa.
Use fabric paint to add decorations to your throw pillows or sofa. Use brushes or stamps to decorate in different images. Use iron-on transfers from craft stores. They come in different designs you can use to match your decor.
Add fringes, beads, decorative tacks or fabric piping to your sofa by putting them along the outline and bottom part of sofa.