(As you can see by the number beside my name!)
This was interesting because I give my photo students the same kind of task. So here it is:
In my mind, the sky needed dramaticising. But I've also been experimenting with desaturating most of a photo with adjustment layers and masks, so that's what I did with the foreground. Extra saturated colours up in the sky, and monochrome trees and reeds. And increased contrast.
I didn't want the photo to look unreal, so I didn't lighten up the treeline or reeds much. I could have spent more time and effort being more precise int eh reintroducing of colours, so this is just a proof of concept.