Hi Robert,I'm not going to hit you or anything because what you are doing is very good. L will however offer some advice.
First the girl. You have captured the facial expression beautifully and it helps that the eyes are looking in the right direction. You could reduce the bridge of the nose and soften down the features in general, but your sculpt looks like the photo. Don't forget you are comparing the delicate flesh tones to the solid flatness of sculpting clay.
As for the hair, that is a fun project all on it's own, and yuo have a great reference in the photo.Where the hair is in contact with the head it can be relatively flat, but as it leaves the head the locks can be looser and more deeply sculpted. The way I do hair is to form the locks from rolls of clay shaped like icicles and then flatened out. Next push them into place twisting and interweaving with each other, finally finish off the detailing with a wettened needle. It sounds easy but it isn't, so don't worry if you take several tries to get it
The size of the hand is defined by taking the width of the palm as the distance between the tip of the nose and the point of the chin. From your photo's, there seems to be something of a lack of space between curled fingers and sleeve, remember to leave room for the wrist.
Regarding the other head, that looks great. Personally, I'd put in some ears, Donald Trump has enough problems with Mexicans without getting him started on Aliens
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Finally a useful book recommendation, The Artist's complete guide to Facial Expression by Gary Faigin
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Best wishes, Gary.