Ok, so on #1 you noticed the similar colors between the bricks and the rusty antenna. We can work with that. You were going for green and red. But you also have blue, a deep saturated blue, and lost of it. And a strong white line at the bottom. And many different shapes and angles. So compositionally, it's very busy. And the red and green's are competing strongly with the blue. This all comes together and kind of makes a mess of things which means the purpose of the image (displaying the green and red) is lost on its viewers. Work to simplify.... whittle down the composition to it's bare minimum... ONLY the things that you were trying to get a cross. Sometimes this can be down before you open the shutter, sometimes it can only be done after, in post. Sometimes it cannot be done. And sometimes, even if it is done, the idea that you had or the thing you saw just doesn't work.
#2 I agree with Scuba on this one... the sky is underexposed so the clouds aren't popping. Even if it was properly exposed, the sky would closely match the tone of the clouds so they still wouldn't pop without some dodging and burning or a controlled black-and-white conversion. You could possibly use a polarizer to knock down the blue depending on which way you are facing. And the silhouette of the antenna and chimney is simply not interesting. It also has a tree limb growing out of it.
Next time, work on cutting the composition down to it's bare essentials. This is the easiest way for a beginner to make better photos.