Step 1: Take the paint card home, cut out the chip you like, and stick it on the wall to see it in your room's lighting. Don’t make a decision based on how a color looks in the store.
Tip: Many hardware store websites have software that allow you to see how a room will look painted in a certain color.
Step 2: Audition a color. Invest in a quart―or a sample size of paint―and apply the color to a two-by-two-foot piece of foam board (available at paint centers and art-supply stores). Position the panel in several parts of the room at different times of the day to gauge the changing light.
Tip: You can have paint custom mixed to match a piece of fabric, carpeting, or wallpaper at most hardware stores. The sample must be a flat item that is of uniform color and is at least 1/2 inch square.
Tip: Ask a paint store to tint the primer toward your finish color if you’re using a dark color. Tinting the primer will reduce the number of coats you'll need for good coverage.