Incorporate some Southwestern color. Shades and hues that are typically used in this style of design include red, light brown, yellow, orange, mauve, purple, pink and turquoise. Use whatever method fits best with your decorating budget to put these colors on the couch. You can purchase or sew covers in these colors and use them to recover couch cushions, have the couch reupholstered in a colorful fabric, or place on the couch two or three throw decorative pillows that have these colors.
Use Southwestern textures. Leather and wool are very commonly used. Make some wool accent pillows to dress up the couch. Cut two equally sized squares of wool fabric. Holding them together, sew three sides closed half an inch in from the edges. Stuff the pillow and sew the last side closed. You can make the pillows as large or as small as you like. Another option is covering the couch with a leather or faux leather slipcover.
Add wooden accents. Pine, poplar, oak, cedar and willow are just a few of the woods used in the making of Southwestern furniture. You can add wood to your couch in a number of different ways. If the back of the couch or sides are visible, consider nailing on strips of wood to create an eye-catching art piece. And on some styles of couches, the legs screw on and off and can be replaced with wooden legs.