Draw manga girls by starting with very round heads. Add large, rounded eyes, without eyelashes, that are set low down on the face.
Finish your girl's face by adding a very small nose and mouth. Your drawing will look more childlike when the eyes are proportionally much larger than the other features on the face.
Create a simple hairstyle for your little manga girl, making sure the hair covers the ears. This will help the reader realize that she is a girl, not a little boy.
Create the girl's body by using a two-to-one ratio with the head. The body should be short and rounded, spanning twice the length of the head. Although this is a young girl, the bottom half of her body can be filled out a little more than that of a little boy.
Add clothing that is traditionally female, such as a dress or skirt with a floral pattern. Ribbons and bows may work well too.
Create an older face for your manga girl by drawing smaller eyes and adding eyelashes. Enlarge her mouth a bit, and make her face a little more angular than the little girl's rounded head.
Add longer hair, and make the style more sophisticated for an older girl or adult female.
Lengthen the body gradually as you age your character. An adult manga character's head-to-body ratio can be up to one to eight.
Thin out the girl's torso and add curves if they are appropriate to the age of your character.
Draw feet for your manga girl that are a little smaller in relation to her body than the young girl's feet.
Add clothing and accessories that determine her age. This can include a school uniform, a shirt with ruffles or earrings.