The ship looks rather plain and I agree the dithering on the sails isn't necessary. But that moon looks pretty neat :D

I think I do need to work on my shading a little and I need to find a way to add more detail to my artwork.

Thanks for the feedback!

Good basic structure, the outline it great, maybe give it a little more oomph next time, different types of dithering, rather than the one, you might as well forget the dithering in this one and go with solid colors, it would make no difference.