anatomy, anatomy, anatomy! I went a wrong way, you don't go that way!
there is many helpful anatomy references, just draw them first with simple lines and try to attend analogy..
if you don't have enough time for these, just use ready base meshes. you can find many of them for free, or use makehuman and sculpt on its models.
and for each part of sculpting process, don't forget to put a reference beside you.
do hairs after all parts.
btw her face is so cute!