This is my process/attempt at this exercise. I had fun trying out different face and body shapes :) I tried to keep in mind the tips learned in this class, it was very helpful, thanks Tom! 

To begin with I tried playing about with different face shapes to see what results I'd get:

I then sketched some different body shapes:

After cleaning up my sketches I then went on to clean up and finalize Sandra and Tiffany's design :)