First of all you should decide what type of people you would like to draw for your kids to fill color in. It is good to make some real people faces for the kids for building up their sense of creativity.
If you draw a family, it is good to draw a man, his wife and two kids so as to make a complete family. You can make it interesting by relating the drawn family by yours.
To draw a man, you should make sure that he should have a matured look with no boyish style. The hairs and dressing should be drawn accordingly.
For drawing picture of a wife, it could be a woman dresses up like most mothers. The hairstyle could be any of the existing ones as well as the dressing.
Finally the kids can be drawn preferably in a way that they look younger and smaller than the parents. A boy could be wearing shorts and the girl can have a long skirt or frock.