This completely lacks any depth and looks like one texture copied and pasted over and over; in fact, it is incredibly hard to discern that this is even a castle at first glance. Have a look at the volumes and textures here. Personally, I think you'd be much better off doing something far smaller, something where you can devote attention to every single pixel. Perhaps try making an avatar for yourself (64 x 64).
Lol, I knew you were going to say that. Alright, the next thing I post will have some actual time devoted to it.