Thanks for comment, FlyGuy. This piece is very old... maybe I'll update this, adding something more on the background.

I think the color you chose to AA the clouds with is to light of a blue. You want to find a happy middle between the white and the blue that way they blend better. You can tell that its too light due to some rough edges in certain areas. I think this is a really pretty piece though

minimalist, i like, nice AA on the clouds(:

Thanks Manupix, I will work in this to improve the volume...Thanks for the tip.

Thanks too tormi1000 :)

A simple style (: 

Very minimalist. Why not?

Check how Robinhood has managed to give volume to his clouds, with only similar colors.

Look for reference images of actual clouds too (cumulus).