If I may, this is my opinion:
The first shot for me is good, but could be a lot better. Now, like with all of what I'm about to write, it's just my opinion so feel free to ignore it
The composition is a little off imho. I see how you have tried to use the reflection as a form of foreground interest, but I feel that if you had used more of the grass as a lead in and contrast in texture, this would have worked better. Also, if the water was as still I think it was, then a shorter exposure would have given you better and more detailed reflections. I feel that you could also afford to adjust the curves to bring the highlights out a bit more.
In the second, the composition is better, but I can't help but feeling that the mid tones could be brought out some more, and in turn, reducing the contrast in the sky a little.
In the third, as said already, the colour / use of sunset filter has made the shot look somewhat unnatural. The composition is ok though imo. The B&W version of this shot works well however, and aside from the grass in the very bottom left, I feel this shot works the best!
In the B&W shot of the ruins, I feel that you could adjust the levels in bringing the highlight slider right up to the edge of the histogram, thereby adding contrast to the shot, as at the moment it's a little flat.
I should make it clear, however, that the shots are good and have a lot of potential! Also, I am by no means a recognised authority on landscapes, so feel free to disagree with my comments