Nice edit, Keith! I would have felt inclined most to work on that one (out of these four), too, but it really bothers me that the can seems to be just ever so slightly out of focus, although it is clearly meant to be the subject, and the curled-up grass behind it did GET the focus.
The first is diagonally divided, which in itself I like, but the sky-corner has too few features. Maybe a bit of careful tonemapping could help: add brightness to the lower lefthand corner part, and add shadows to the sky?
Maybe like this?
I threw a lasso around the "stoney part", feathered it some (12), upped the highlights of that part (and upped them some more in the rock formation up left), then went to "inverse selection", upped the shadows and lowered the midtones of the sky to bring out the clouds more, and in a later step added saturation to the yellows and reds of the "stoney part".
I feel there's some haloing going around the upper rock, though, which is NOT good...

- but all in all that's my idea for this particular photo.