To create a casual feel, you might need to replace light fixtures of brass, porcelain, china and crystal with fixtures made from wrought iron, tin or wood. Casual lighting is much more likely to have a lampshade. Chandeliers should be simple; definitely not crystal.
For another decorative way to give your décor a casual new look with lampshades, try adding a touch of color by hot gluing the ends of wire ribbon to a canvas lampshade. Using two dowel rods, glue each ribbon piece over and under, creating decorative loops. For a really polished, finished look, cover the top and bottom edges of the shade with ribbon as well. Wait until the shade is mostly done to flatten your ribbon loops. This will give you a better idea of what the finished piece will look like, letting you concentrate on getting the details just right.