Add dots of color. Roll fondant into a ball, kneading until it's soft and pliable. Using a toothpick, add dots of icing color or drops of flavor in several spots.
Helpful hint: Tint a small ball or enough fondant to cover a whole cake. As with any icing, tint colors at one time; matching colors later may be difficult. Add just a little of the concentrated icing color at a time, until you arrive at the exact shade you want. If you'd rather not mix color yourself, use pre-tinted fondant in a variety of pastel, primary, neon and natural shades.