I like the forests. If you wished, they could stand to have some internal texture, but I don't think that's necessary. I notice there are light and dark areas. Are these mountains? If so, they definitely need to stand out more. Also, I'd say that internal texture is necessary for mountains of this style.
What program are you using for this? Whether it's GIMP or not, you might find this section of RobA's tutorial useful.
I think you're on the right track with this idea.