Cool planet Backsept... maybe a tad obvious cloning but damn nice colors.
Here is my W.I.P
Now about them cloudmaps... Try first using something already existing. Slap them on a sphere slightly larger than the surface, basically follow Deks' tut. Then make sure you make them really, really white, either by faking some using self-illumination (yeah I know it's cheating) or by carefully, carefully embed some specular into the cloudmap. The later can backfire if not taken care of properly resulting in more or less silverish clouds, cool, but not very realistic.
To liven up your already made world, you can play around with ocean specular and some small amount of irregular land-specular, especially for the desert regions. Also a more detailed gradient in the atmospheric falloff will help.
Hope I just did not confuse ya'll here. Questions !? just fire away
//Asz