I came to Poser stuff from photography, though my kid brother is the real camera geek.
Anyway, I think you need to pay attention to the lighting setup, and possible the skin settings.
No doubt. I am fairly new to DAZ I and lighting in general. Much work to do!
What I'm seeing is a picture where the camera's exposure metering is dominated by the white background, which gives underexposure, and with that skin tone underexposure is really bad.
Well, it's obviously hot that, as DAZ doesn't care about the background - it's not sophisticated enough for that

But the lighting in general is something I need to work on.
Anyway, the clothes show that the lighting setup could be improved. A fill light close to the camera would just lift the shadows. In Poser set it not to cast shadows.
The shading model implicit in Poser and DAZ Studio seems to be the
Phong shading model. A lot of Poser textures can be greatly improved by adding some Ambient channel to the mix. It substitutes for the general light scatter from the surroundings, and the latest versions of Poser do have other ways of getting around that missing element.
For this particular slot I'm using a single key light together with
Pendragon's ambient environment light and skin shader (DAZlstudio only, I'm afraid). Should really have put in a fill light too, but didn't bother for this W.I.P shot, as I was more interested in the face being right, rather than making an actual portrait. Not sure that's an excuse

The clothes, incidentally, I just left with their defaults, so there's a lot of room for improvement there.
For dry skin I'd set a low specular value, with relatively large reflection area, diffuse at about 90%, and let the missing 10% come from ambient. Diffuse and ambient take the texturemap as an input. Specular could be a very desaturated version of the base texture colour. For wet skin, up the specular reflection, and make it a bit less spread out.
I shall have to fiddle with various settings, and see what works. I'd say I'd start with your suggestions, but I currently only have the Net at work, and by the time I get home I'll probably have forgotten
