Composing - Desert Outpost

Just another attempt to improve my CGI skills with MoI3D and Photoshop. As background I used a picture I did in Bardena Reales in Spain. My main problem is the texturing in Cinema4D. I feel that I don't learn anything. I see no improvement and I have many problems. If I solve a problem I create two new. Is there anybody who can help me? Maybe with tutorials or own experience? Perhaps it's a good idea to work with Blender. Currently I use an old version of Cinema4D for texturing, lightning and rendering and it's really complicated for me as an hobby artist. What do you think about this picture? What can I do for realistic results? Hope somebody can help me.