When it comes to choosing a color, as a rule you should never pick the color for the customer. It is fine to assist them but make it known that the final decision is 100% their choice. Paint half of a small 12” x 12” piece of drywall black and the other half medium-gray. Take the paint chip and hold it up against each half of the drywall. This will give the customer an idea of how the color will look on the walls once it dries. Most of the time customers can pretty much narrow down their color choice to a couple of shades. Your best bet...