Well the first one is ok, although you should try a better camera.
The second one is too plain, you have a small road in the middle going up a small hill and a few trees and shrubs on the lines of that road. Add a forest behind the hill or something and also you should smoth out the edges a bit more.
The third one is ok although it's a bit to plain again. Add some shrubs or rocks randomly on the grass.
The fourth one is too pain on the front side, once again add some rocks or shubs or something and use the smooth tool for the mountain behind the statue.
The fith is good, but use smooth some more and it seems that the last tree is floating in air, use some fog as well.
All in all it's ok for a first try, you have potential, try looking at some other terrain picks and see what they did, then try to replica that but in your own style.