I like your style, especially the color. I think the mountains need to have more depth though, more height, more shadow. They look a little flat or just kinda rough, some peaks woudl be nice, unless they are just foothills ofcourse.

I also think the rivers could use some more integration into the lanscape. They really look like a layer abover everything else. How do they affect the landscape? Maybe they make it dark, or lighter, or sandier or more fertile, or they are in low lying areas, valleys and such. Do you get what I'm saying?, maybe I am not explaining it well though.