Agree with Drako. Also the grass is too random and noisy, it should have less detail the further away. Perspective is off too, the path should be much narrower on the left side.
Nice colors and atmosphere, I'm sure you could turn this into a really nice piece with some more work! ;)
For a start don't use the dithering. You must understand basics of drawing and colouring. Anyway, the sky is pretty cool. I recommend Derek Yu's tutorial to you. enjoy pixelart and be better and better ;)
Gostei *-*