Although it looks fairly good, and has some atmospheric tastes to it, it is still lacking in some details and variations.
You can follow a tutorial to help you with that though
Anyways, if you don’t want to watch the video:
You should add variation to the landscape, hills, small holes, rocks, debris, plants, shrubbery, etc. Give it landscape feel, don’t make it completely flat.
Think of it as this, have you ever seen a completely flat landscape with literal no shrubbery, rocks, etc? I mean, you might’ve (in photos and stuff). However, commonly, there are a variation of shrubbery, trees, sizes, rocks, plants, and well, life.
Texturing and lighting is important as well. Even though you may think the moon may not have “sunrays”, it does still emit rays of it’s own. I don’t know if the sunray’s work with the moon however, its important in that regard .
Adding depth of field may be a good taste, color correction, etc.
Small details can go a LONG way, don’t space out from adding them