Have you tried a circular polarizing filter? Since both of these are landscape shots that were taken during the bright part of the day, you might find that using a polarizer is useful. What polarizing filters do is darken the sky, reduce reflections, and generally increase contrast. You can read some more about polarizers
here or
here, and there's a good
example of the difference a polarizer can make that I found over at Flickr.
I'm in a bit of a minority I think, that I prefer filters over photoshop, so I will say that it is possible to replicate some of the effects you can get using photoshop, but not all
