I reckon Kemal's idea of making the planet bigger is cool, I'd also change the b/g starfield, create one in an image package and wrap around a very large sphere as though doing an HDRI. That way you can add cloud fields and other space things. There was a great tut recently mentioned on here for creating star fields, but I can't remember where on earth it was....

----------

Toolset: Blender, GIMP, Indigo Render, LuxRender, TopMod, Knotplot, Ivy Gen, Plant Studio.