A procedure for painting clouds which is easy to achieve - and a starting point for further enhancement, if needed.
Since it's so expensive in terms of time and effort to render good looking clouds in Blender, i will continue learning how to draw them by hand. But luckily most of the times we don't need photorealism for telling the story. More important is to have a cloud design that fits the mood that you want the image to have. Soft shapes for friendly images and torn, wild forms and high contrasts for drama.