I like them. I see where are you going and what you want to achieve. You still need practice but i can sense some fast improvement with some practice. I would suggest to try to paint with photo refs of landscapes, buildings, some details like trees, grass, sky, etc. With this practice you will learn how different object/materials look and behave in real life(that is why you should try with photo ref)
Then you should try to find on this forums some threads/tuts about planes(f.e. you have many images that have same contrast and details in foreground and background)
Also, don't use lo res photos. Especially is you strech them bad pixels will be seen.
When you paint use color from image(photo) it self. That is also good practice.
I would recommend Dylan Cole dvd's. He is one of best matte painters, and he use allot of painting(you will be suprised how easy this looks, and his brush strokes are so loose) in his matte paintings.
Hope this helps