rotate the eyes inwards slightly. Turn the corners of the mouth up.
Manually model the eyebrows:
make a few variations of thickness, of single hairs, out of splines, make a vaguely rectangular / eyebrow shaped array of them as instances, , group them, use a lattice to shape it to the brow/ and taper, then manually adjust the splines as needed.
Right now they're way too thick, and dense, and dark.
You might also try creating multiple textures of an eyebrow and layering them with multiple meshes.
Keep in mind that there's no "correct way" to make this. Even if you're planning on rendering close ups of the face, doesn't mean transparent textures can't look good if made well.