Some hair color brands that can be used for coloring gray hair include Umberto Beverly Hills U Color and Revlon ColorSilk. Products for covering partial gray or touching up gray roots include ColorWow and Christian Dior's Mascara Flash for Hair.
When dying gray hair, use two boxes of hair dye: one that is the desired color and one that is a little darker. Apply the darker color to the roots and the lighter shade to the rest of the hair. Gray hair is more difficult to color closer to the roots, so using two shades ensures even coverage. Once colored, use moisturizing shampoos, conditioners and styling products to keep the color from fading.