Pretty good composition, too bad the image suffers from too much noise, did you try to despeckle in PS? Consider a tripod and lower ISO, and also straightening the windmill.
Meets the challenge, but is lacking a bit in technicals. Good job of following the rule of thirds for the placement of the windmill but it looks as if it may be a bit underexposed which makes it noisy. If you take it into photoshop and use levels to deepen the darks a bit, you'll lose some detail in the ground but increase the contrast and enhance the color in the sky - it will have a lot richer look to it.