Hey @Alessandro Dalponte! Great concept! I did a paintover concerning general composition things. But as for color, the image is dominantly on the cool side so it starts to flatten out. The scene is lit like a sunny day so we want to inject warmer colors to be consistent with the lighting- and painting the feeling of warm sunlight hitting the aqueduct would be a nice moment to capture. Painting the field of grass with greens closer to yellow also helps capture the daylight. This allows us to create depth as well by painting the mountains a much more blue and desaturated green in the background. There's a spectrum of warmer to cooler in all colors- these temperature shifts make a painting more believable and interesting! But again, cool concept and great work!

I really like the colors in this one, you added a bluish hue to the mountains in the back while keeping the stronger darks in the mid and foreground. And the clouds provide an interesting almost Pixar like aesthetic. One thing to note is the phase of the moon in relation to the main lighting of the sun. If I’m not mistaken the moon would have more of a gibbous shape towards the light source.

it's pretty and fun. 1) your clouds are pretty cotton candyish. that's a style thing- so 50/50 on that. 2) going to have to reverse the light on the moon, (or else you are in a system with two suns... but that still doesn't work because the light that is hitting the scene would still be hitting the moon in the background) 3) I'm not seeing enough temperature change in the shadows on the grass in the foreground- and the hills in the background need more atmosphere perspective turning them grey like the sky in the horizon. - did you have any reference for the color palette on this? Without one, this is mostly subjective and it will be hard to get it "right"