Just look at these two. The red hair is a perfect color match with the sweet little green skirt as well as the rest of the background. The yellow works well too.
The older sis, being serious and, well, an older sister, colors are great because although she is important; she is a nice counter to the red as well. she is in colors that meld well with the background and make the entire piece work.
Getting ready for the Halloween season. Again the yellow band is a nice contrast to the purple as they are opposite colors. well done.