This is my first render, any advice would be highly appreciated.
Unfortunately I was unable to get moon texture within cycles render and added it in GIMP.
The moon itself is an UV sphere with the emission bsdf material. Is it possible to get the same looking moon with cycles?
Yes there is. The material settings for blender internal and cycles are very different. For cycles, you have to add a new material > click the box on the right of the color panel > then hit image texture and select your image file. Hope this help! And for advice on your render, add more foliage to the landscape. I see you’ve added a couple of cactuses, but perhaps put a few more and add little patches of grass here and there. For your first render, its not bad
As a first render it is pretty good. Imho you should place the camera so the viewer can see the depth, right now it looks like the river and the hills are suddenly ending. Maybe slightly decreasing the focal length of the camera would help, also I would make more of the hills and river so you can really feel the depth and distance. And I would place the camera so the river seems to go down.
For the background, I would use stars. Moons seems okay, maybe adding a little bump will go.