I have never worked with clay and i don't know how much experience you have with it. But maybe i can give you a few points to look at. But don't get me wrong. This is a good start but there are a some points that can be improved.
At first i'd highly suggest using an armature of some sort. Some sturdy wire will not only give you a nice solid base to sculpt on but also forces you to give more attention to pose and propotions before you even begin sculpting. And use a reference as it will help you in planing out what you want to do.
Maybe you can use
http://www.posemaniacs.com/ as a reference - not only for poses but also propotions.
Also the descripton of a belly free female model normally suggests a sexy model. For that your model is to thickly armored and as a result looks too bulky. Also the massive belt looks weird as the waist is so thin compared to both the belt and the torso armor frameing it.
What i'd try is to do is draw more attention to the belly in makeing her armor more form fitting. Also if you want her to be sexy you can shape her armor in more female propotions. Let if curve like the human body and maybe even add a few details on it that are muscle-shaped. Either with additional plates of armor or just shape the basic plate like that.
But if you want the model to be bulky and strong looking I'd also bulk out her waist some more.
The surfaces of your model are looking kinda rough and not smooth. Yes you could sand them smooth once hardened but why not smooth them directly. Just try useing a wet finger and smooth it with that. And there are some spots and areas that will be hard to sand like between armor plates and the like.
You said it yourself but the feets will need some serious work.

And it will be really hard sculpting them hanging in free air. So if you didn't do this already sculpt your feet against the ground. This way you can make sure tha both feet are correctly aligned and the model stands upright. And the biggest win is that you can press against the ground and won't have problems with the feet bending while applying pressure or removing material.
It looks as your legs aren't the same length. One is lightly bent but even with the bend it seems to go further down. It could also be due to camera perspective but better save than sorry. So you should look into that. Either lengthen one leg or twist her hip if there actually is a problem.
And personally i'd tone down the width of the lizard skull. And you might want to consider rounding the eye holes some more as actual skulls normaly have round eye sockets. The more slit like approach creates a more evil and demonic appearance. (But that might even be what you are aiming for?)
Also as the scale for 28/30mm models is really small i'd suggest not useing clay for all of the details. (Or at least not add them all in one step) Personally i'd just build the basic body and maybe the armor depending on the shape of it and then let if cure. The rest of the details i'd add after that. Some clays can take multiple baking steps but maybe it is enough to only bake the body slightly so that is is hard enough to not get warped once you add the finer details. Alternatively you could add the details useing two part epoxy putties like greenstuff as they don't need baking to cure.