Use an off-white base coat for a golden brown or yellow-ochre glaze wash, which is one of the most popular faux-finish techniques. For a darker finish, use a base coat in a slightly darker color, such as deep beige or taupe. Understand that a faux finish is generally never lighter than the base coat.
Pick two colors that are on the same paint strip -- one color that's darker and another that's lighter. Use the lighter color for the base coat. The other color can be two to three shades away from the base-coat color. The tone-on-tone look works well in both modern and traditional settings.
Look at fabric colors in curtains, throw pillows and even place mats for inspiration. Examine artwork in the room for additional ideas. Flip through magazines and interior design books. Visit a home-improvement or paint store. Many have small faux finish swatches.
Practice the technique on a sample piece of cardboard. Not all colors work well together in faux painting. Do the technique the same way you intend to do it on the wall, using the same paint colors and tools. Purchase small sample cans of paint for practice.