Idk if I like the color of those rocks. They'd do better with a slightly red tint.
Not sure if I care for the rays of light either. I know they're kind of your thing, but if the top half of your sky is going to be that dark then there isn't going to be a sun up there with it. It's gonna be a sun with a lateral trajectory of light, which will be most evident in its coloration at the origin and the destination. Though, dips in the clouds (which are usually quite sparse) will reflect the sun's light, it's probably too much work to try and incorporate all that - best to just have the sourcing of light be at the origin i.e. the left space.
As for your foliage, I've found that cleanliness is kind of essential to this style of terraining. And as such, you want to try and incorporate any unsightly models into more attractive models, as they make sense of course (placing the deadwoods near the pine trees as an accent to their shape and affect). For the most part you do this quite well, as expected, but some key aspects are pretty jarring, like the aforementioned trees, as well as trees seeming to float just a little too much, and the pretty atrocious effect that the tall bushes make when put in front of a fogged background. Also, you want to get as much mileage as humanly possible out of the tools at your disposal, one decision I made early on in this field, is to never use that fucking pre-made variation of the tree model, as the top intersection between leaves and trunk makes for such a god awful highlight of the terrain. Best to just use the separate models and copy paste the two over and over again.
Last thing, scrap that rock tile. It's shit.