The most important when drawing a female is the curves. Correct structure of curves make a female look like a female. When you change the proportion a sexy female could come out a little more weight on her. But even when drawing a hawier female you have to follow the proportions. The structure are all the same when drawing a female. Just remember, the more curvier the female your going to draw, more sexier they going to come out. Follow the example and you'll see the progress in no time.