You may decide to make people yellow, blue or green. There may be good reasons to do that, but it shouldn't be because you can't get the skin color right.
Download the Kids.fla movie and make each of the children have a different skin tone. Experiment and see if you can represent the whole human race.
INDEX, RGB Colors, Selecting a color, Kids: Getting skin color right
Next lesson: Movie Clips: Drawings in the Library