Ok, here's the next set of ideas that I have.

1.)  You are (at least I'm 99% sure) rendering this in direct line with the light you have in the scene.  I would suggest moving the light to the right or left.  Then you will be able to see the dark part of the planet.  The way it appears at the moment, the light is just above the camera and the camera isn't at an angle that can see the dark side.

2.)  I'm going to make a guess here and assume that you have put the starfield into the background and not the backdrop?  If that is the case, switch it and see what happens.  My suspician is that you will then just have too many stars.  Try it and let's see.

3.)  You need to reduce the amount of glow in the sphere that has the planetary halo a little bit.  I'm not sure but I also suspect that you may need to adjust the gradients somewhat and I'm also 99% sure that you haven't turned on the "point at" behavior to have the atmospheric glow sphere pointing at the light source.

4.)  I think you need to make the cloud sphere just a tweense bigger (like 1% bigger).  I make that assumption based on the fact that I don't really see any cloud shadows.  However, that could be an artifact of the way the camera and the light is positioned so let's wait on that a little bit before we jump off the deep end.

Lastly, don't say the attempt is feeble.  The bottom line is that there are gobs of little details that require a lot of dialing to get it to look the way  you want.  Don't worry now.  It looks like the hard part of just having something to work with is already done.  Now you just need to dial.

I won't be able to monitor this thread for a while so if you have more questions, it may be 24 hours before I can get back to you.  This is going fine.  Hang in there.

-Kix