Ooooooooooooh! =o

Think you hit the nail on the head with a bunch of points here - I love your edit. The contrast/shade issue on the dunes was pretty obvious by the time I was finished, but I didn't have enough time to rework them by the deadline.

Maybe I'll go back to it one day... I still have the PDF :)

Yeah, I don't spend more than an evening on a piece, once it's done, it's done, warts an' all!

The composition is quite wonderful and I think this piece has a lot of potential. My least favourite part is the way you've used colours. Here's my humble EDIT. 

• Things further away tend to blend in more with the atmosphere, which means that if the sky is bright and blue, things further away are more bright and blue. Things that are near will have warmer colours by comparison.
• Things that are closer have more contrast
• Even clouds are more interesting to look at if they have a bit of colour. I don't like the use of grey in this piece. You may not like the yellow-ish dust clouds, but you could go with another colour.
• It's a bit tricky with the light source in this piece, because the dunes all look like the light source is on the right side, yet the mountain in the distance looks like it's directly under the sun. The top of the clouds should show the light source(s).
• I think it's slightly unfortunate that the character's head seems to touch the border of the distant clouds. It would be better if the border was further below or above her head.

Just my 2 cents. I'm no expert when it comes to this stuff, but I'm sure others will correct me if I've said something silly :)

what a beautiful palette! Some of the lines, like the mountains, could use some cleaning up, but as a whole I really like this piece :D