colour and light

I have a bad habit of getting lazy and messy when I colour digitally, which is passable for studies but not so nice in bigger pictures. It takes longer to paint with traditional principles, but I think it's well worth it for the depth and liveliness that I find missing in my hastily coloured digital stuff.
This picture is an example of me trying to apply that - I painted it in photoshop in the same way I paint with acrylics, and I need to fix some things, but I like the way it's going.



I have an idea in the back of my head about a sort of dystopic lizard society in a desert, and so far the way the story pans out is a little morbid and lacking in details, so I'm going to keep thinking about that.. But I thought I would start posting a few ideas about colour and lighting and go from there. I've actually got more recent stuff than what's below here, but it's saved on a computer at my parents' place.
..Which is a bit weird, come to think of it, because there's no tablet or graphics program on that computer. Why are they there?! A mystery for the ages. I'll post them when I get them. :)