Hey, it looks good for me!
However, there are three things I would like to point:
1 - I see very little height variaton in the ground in front of the fortress. It's far too plain. It'll maybe look a bit better if you give some variaton to the terrain.
2 - That lonely torch... it seems somewhat out of place for me.
3 - I think that fog has a extremely high contrast with the sky. It's at night, so you should use a darker fog.
The insides of the fortress look decent to me. If this is your first terrain, you're having a good beggining.
That's, at least, my opinion.
Regards