in blender, i made a nice grass field, a nice oak tree, and it took two nights but couldn’t make a sky 
and thus when i put all together with a stock image of sky, it looked like crappiest photomanipulation done by a newbie who just learned gimp or photoshop damn!
I ain’t touching blender for next two weeks 
it is good to try something other than just sitting and thinking for the best work. My experience says that the best work don’t come in first attempt but in many.
So if you are leaving blender for 2 weeks that means you are loosing that much time in which you can improve yourself :). For me 2 days are much and you are talking about 2 weeks.
Hope that helps , Thanks…
Even the best CG Cookie tutorial uses photo background… Hide it better ;).
Have some constructing exercise done meantime, experiment with some materials…
No hehe, actually i can’t sit doing nothing with these - if not blender, i will do something in inkscape but will keep doing 
I just can’t make a solid output because holidays are over But will keep doing experiments in blender until next weekend. And I must learn to model the damn sky!
Yeah obviously! You’re right. I must learn many things myself, that’s possible only by experimenting!
Hmm when i looked later, it doesn’t look bad, just I couldn’t master the internal render, so the photo lost it’s clarity (i just put 2000 passes in cycles, but in internal it’s way difficult!)
yes I also find the internal render quite difficult, like cycles gave result in with less work or so. :D.
There’s actually a technique in professional filming where a photograph or painting is made or found and used as the background for whatever animation or film they arevdoing. I believe this is called matte painting.
i use this technique for stars sometimes (especially because using the world stars when your clip limits are 0 to 1000 or greater floods the GUI with little white dots and bogs the system down. And rendering is not much quicker apparently).
The rule of thumb with the built in stars is that you adjust the distance between the dots with the clip distance.
From what I know, the stars feature is an old scanline-based technique implemented before Blender had raytracing, while it is usable in some instance, it’s useless in others because they do not get raytraced and thus will not appear in reflections or through refractions. One of things you can do now though is switch to Cycles and use the voronoi textures along with others to create a stardome that might even contain cosmic dust clouds and nebulae.
In fact, the old star rendering feature was almost taken out completely during the 2.5 project because of the ugliness of the code, so I would personally switch to Cycles for your sky generation or use images.