Iuvenis_Scriptor - I don't confess to being an expert & I've never made anything for sale but what stands out to me when seeing characters in the marketplace is a look which quite obviously says this is V4, which does put me off unless she has amazing textures.  Don't get me wrong, apart from the eyes & eyebrows which has already been mentioned here, I like the fact you're attempting to create a product. You say you want realism, I think her face should be morphed more to take her away from an obvious plastic V4, and the skin texture, this is crucial. If someone wants to do a portrait then those textures have to hold up. I really hope you succeed in what you're doing here, good luck!