I had recently watched a very instructive Gnomon DVD about matte painting from the Gnomon Workshop.
Although matte painting is definitely not my field, this DVD certainly inspired me for a moment and so I wasted no time and downloaded a heap of Photoshop brushes. They're easy to find on the web if you google them but if you're interested you can start looking for some here. Trust me when I tell you that Photoshop brushes can do wonders while saving so much time, especially when combined with layer effects and other photoshop features etc.
This is something I whipped up in just under an hour after playing around with my free downloaded brushes (it's not much to look at but it says something about photoshop brushes - I think). The workflow for this was simply using a combination of ready-made downloaded brushes for rocks, leaves, clouds, hills, ocean, the bird, etc, all just composited into this one image, no manual handpainting but only composition.