When shooting a photo we generally break it up into thirds. If you are showing the sky then one third foreground and the two thirds sky. Conversely, if we are showing the ground as the point of interest then one third sky. We try to avoid splitting 50/50. In your original photo your horizon is nearly running through the middle.
In Don's edit he brought up the shadows so they weren't so dark and cropped the photo placing the foreground as one third and the distant backdrop and sky as two thirds. This did away with some of the uninteresting grassy area and gives more prominence to the distant mountains, clouds, fog, and the sun.
As a general rule, and knowing when to break the rule is also key, we try to break an image into thirds as well as place points of interest at the intersecting lines. Sometimes we want to break the rule for a certain effect, but when in doubt... try to see the thirds in your minds eye as you frame your shot.
Finally, editing is your best friend with digital images. Shoot the best image you can and then tweak.
Welcome to the site.