I'm sorry, I'm just not a huge fan of the set. I agree mostly with what's been stated.
#1 - for me I see the curved road, but it all gets lost with the surrounding grass, its all gray. Then guardrail is like a neon sign bright. The road S curve is the subject, and its totally lost with everything else. I could care less of the sign, honestly I think it detracts. What I've heard is anything that doesn't ADD to the composition detracts. Simple is better, try cropping it out to say a 4x5.
#2 - sorry, don't see much here.
#3 - I might say you went the wrong way, I'd try cropping most of the ground and leave most of the sky. Again, the corn and the grass all kinda blends, and its right in the middle of the shot, its just muddy. The sky and clouds have clear lines, but are close in brightness. I'd try cropping the ground, and dark the blues and up the white point to push the clouds brighter.
Good works in progress.