Brush techniques and a wider library of select textures make a world of difference. what I see here is under completion as well because it is obviously unfinished. so as a suggestion: for the background, mainly for the river and forest top/grass, what ever it is, add some dark greys and blues to steer away from a less saturated finish, plus it will provide depth not only due to its distance from the height of the foreground, but make it easier to imply shadows of the trees you are building around that part. Also, on the tree towards the left of the composition, add more shadow to match the shadow on the right tree. but only towards the far left. the light will slowly transition to dark on that tree to the left. It will make the light appear more natural.
I'm new to it too! So do forgive me if this advice is a load of crap - but here goes.
1. Use references. Not sure what a forest canopy or river looks like from the air? Get a photo!
2. Block things out first. I think this is the best advice I can give you. You've gone into heaps of detail of the rock (Weeks worth!) but you haven't got past even the base layer for the forest floor and the buildings look like they've just been shaded under pencil. Try and work on the piece as a whole - that way things are less heartbreaking when they need to change.
3. Those silver buildings? I'm not sure why they're silver. To me they should be the same colour as the rock as if they've been hewn out of it.
Yeah I'm a little disturbed about the silver buildings too. And I do plan on making them as much as the same color as the rocks but I just couldn't get the right yellowish shade either =_=' I suck at coloring too lol
What you might need to learn is brush techniques. You have a few brushes to work with, but the main two are the hard and soft edge brushes. If you need to show edges in the texture then use a Hard Edge brush. I use that to draw bark on a tree and leaves on the ground.
The Soft Edge brush is good to draw a blended sky, and clouds, and then use smugde to make clouds show wind drafts shifting the clouds, or streaking them. I also use a soft brush for grass and moss, but the only reason why moss looks like moss and grass looks like grass is because of brush strokes and patterns.
When you work on a technique, you develop your own movements. If you need to move in a way that is not easy to do, but look great then you take a lot of time practicing the movements and build up some muscles in your hand if that is what it takes.
After you are good with a lot of patterns, you gust think grass, and start filling in with a pattern and in a few minutes it looks like real grass. You only feel like it is just a better way of sketching, because you are finished when you are done sketching.
That is what you should try to do, and everything you have not drawn before takes practice until you know the best pattern.
It might not be easy at all, because you have to understand the nature of what make it look the way it does. Study it's pattern, and no matter how random it looks, everything has it's own pattern. It is how it is identified.
I started drawing a sketch, but while I had the idea, I decided to quickly draw in patterns to give it a finished look Most of it was quick and easy to draw, but some things I took a little more time. I could use more practice doing a quick sketch of scenes.
It is sort of like speed painting with a lot of things, besides the patterns, you have to briefly draw the details and had a little more detail later, but with distant blur you don't want too much detail.
I'm having a little difficulty adjusting brush settings too. I mean I kind of don't use a brush that's 100% in opacity and 100% flow. I used it once for the base of the rocks, but other than that, using it for the shadows and lights makes it look weird for me :/ I got a lot to learn lol xD
You don't really need to fill in a area, I just like to block anything from showing underneath.
The flow makes the leafy look with out fading the shapes and patterns, and the different colors shows the shapes. You don't want the colors to blend very much because you lose the shapes. You can adjust the brush flow until you see the leaves show.Some leaves on the ground might be decayed and they blend in more, so it is a mix, to get what you want. If it is fall then you don't want any blending, and you might need to start with darker color to show shadows under the leaves.
Using variety of colors you can scribble one color over the other and keep changing the colors until it looks like leaves. Then just draw a few leaves on top.
It's a working concept, but require more work to be pulled off. The biggest issue I have is with perspective. The lines of the houses doesn't seem to add up with each other. Look up the correct perspective, and apply that.
I also agree with the fact that you've used your paintbrush as a pencil. Look into some speed paintings on youtube and see how they use their brushes - most people will use large and rough brushes for the undefined background, and use smaller detail on the, well...smaller detail.