Hey there, I'm by no-means an experienced painter (been in the hobby for almost 2 years)... but I'll say this much from just flicking through your images.
First off, some of your models look like the paint was applied a tad too thick, (
http://www.dakkadakka.com/gallery/106768-.html?m=2) the belt buckle on this bracketed image, for example...
But, I do like your style, it's quite different from the norm and frankly one I'd personally find harder to pull off, your lighting seems fluid though that could just be the model reflecting light from your photo-setup
However, perhaps the most important criticism/point to make is your photography... with a lot of these models, they're not quite so OMGWOW in person, it really is down to the process of creating a picture. Your camera seems a tad out-of-focus in some of the pics (but sharp enough in others I guess) and, if you want to look all professional, it's worth investing in constructing a photo-box or whatever it's called to create proper lighting, as you do lack this in a good few of your images.
Another points regarding highlights... they're widely considered optional and from what I've seen it really depends on your style, I'd say your Grots and Orks look absolutely fine without them but when it comes to your guardsmen, you could really use with some on the flat and dull surfaces... There's no need to go too over the top, my style is perhaps an example of that (I use colours that are noticeably a lot sharper than the base colour, meaning it ends up looking a bit more cartoony). Just mix up your base colour and lighten it a bit, then apply it thinly to the edges. Your guardsmen's guns would look a helluva lot more interesting then.
Finally, I suggest looking up
GW's guides for painting faces as I think some of your guard seem to be painted with one colour on the face, though that could be the photo-quality. Generally you want your basecoat, a wash to darken the crevices, then a 50/50 mix between your basecoat and a lighter flesh colour over that on the risen areas and a final highlight. In my case I basecoat Tallarn Flesh, apply a wash of Ogryn Flesh and then add a 50/50 mix of Tallarn Flesh and elven flesh, usually on the cheeks, nose, and the rest of the face (except for sunken areas such as wrinkles, scars, eye sockets, etc...) then you highlight along the real prominently risen areas like gaunt features, the brow, the tip of the nose, the edges of the face, etc. But this is a tad basic and if it is your photo-quality then I'm probably coming over as quite patronising!
Anyway good luck, sorry for my erratic typing style, I'm about to go to bed...