I did this shot about one year ago in sardinia. It took me two minutes to take the photo and two hours till it looked fake enough to use it in my desktop slideshow.
After creating a hdr of three pictures i softly focused the foreground to give the water a blurry effect. I redrawed the contours and masked the details i wanted to keep while setting new highlights and adjusting the curves. I finally set some gradients for the midtones and highlights and shiftet them gradually into the key spots.
Good job!