realistic (or kind of) clouds test

Hi all,
I’m making a cloud test for the background of my 3d pictures. I’d like it to be realistic or at least very believable. I mean if I needed it to be perfect, I would take a photograph. I’m looking for a CG look, but very well done. I guess you know what I mean.
Anyways… Here is a night test:

http://users.skynet.be/igorsandman/blender/cloudy-test4.jpg

I’m quite satisfied with the result, but the bottom of the picture is teasing me. There is something, but I can’t put my finger on it. I guess it has to do with the perspective or the lighting. Can anyone tell me? And apart from that what do you think of it? is it realistic enough? what should I do to improve it?
Thanks.
-IS-

PS: Don’t pay attention to the round artifact on the left. I don’t know what happened, but I’ll fix it.

It’s kinda hard to tell what’s “wrong”, perhaps when you add a foreground it’ll look better…
btw looking at it gives me the creeps…I see all kinds of evil/ghostly/demonic stuff(is it on porpuse?) :o

IMO the clouds dont seem to have enough definition, so they have kindof CG ‘blobbyness’ to them.

Its really good actually, i really like the way you put the moon behind the clouds there, i assume thats what the lights are for, but the shape of the rest is too regular, its obviously CG, try using a layer on top to fade out parts of the clouds, the best way to learn how to do this is to look at the sky at night or a picture. If i want realism in a photoshop project of mine i will always have real reference material, so i can look at what the real thing looks like, but keep up the good work, honestly i couldnt have pulled off that sweet lighting effect!!

hmm, i think you need gaps in the clouds, particularly at the bottom. if you want a cloud filled sky, you need to compress the clouds more vertically the closer you get to the bottom, to simulate perspective.