For the face, it'd be great if you could show a front / three quarter / side close up, like this (without the hair, ideally)
Use Asoro heads as a reference, i can already see that the distance between eyebrow, nose and chin are not "equal" distance. Take my stuff with a grain of salt, cause i am by no means a character artist. Look at Andrew Loomis sketches and asoro heads to figure out where your face planes are and work them out firstly in a very rough pass in Zbrush or blender. Afterwards, if you need more dense mesh, you could subdivide it to get more density to work with. Your sculpt also have some bumpiness around chin area and head because of this . keep going!
heyfor the folds, did you already try the cloth simulation options you have in zbrush? might be a good try to get more realistic looking folds