your problem is you are getting used to drawing boobies as circles. Boobies are more oval as gravity has an impact on those fun bags. Keep that in mind when drawing a female figure.

Also females tend to be very curvey instead of having abrupt edges and sudden changes in angles.

http://www.dragoart.com/tuts/pics/13/1451/6087/how-to-draw-anime-body-figures-step-5.jpg (Unsupported image host)