Visit a paint store or paint website to look at different shades of natural brown. Select the one you want to use for your walls, and ask for a small sample.
Using the paintbrush and sample, paint a small patch of the wall you want to paint brown to see how it looks in the light specific to that room.
If you decide that is the shade of brown you want to use, measure the room and get the exact size. Then purchase the amount of paint needed to cover the wall.
Prepare the room to paint it by wiping the walls down with a sponge, water, and soap to remove dust and dirt. Move any furniture out of the room, and place drop cloths on the floor. Line electrical outlets and molding with painter's tape to keep it from getting smudged.
Cover the walls with a coat of primer. When it dries, apply the first coat of paint. Let the paint dry, and decide if you want to add another coat to intensify the color.
Choose an accent color for your room. You can use different shades and tints of natural brown, a color next to brown on the color wheel, or a color opposite brown on the color wheel. A wide range of colors can be used with natural brown, including yellow, lavender and blue.
Using your paint chip, compile a list of the different shades and tints your accent color is available in.
Obtain furniture, pillows, throw rugs, ceramics, art work and other decorative pieces -- in your selected accent color.