Catalina - I find that you are too far away from your subject (the man working). There are too many extraneous objects in the shot to take our attention away from the subject; so get closer and see what that does; eliminating the red table on the left and the bright yellow pails too. I would also crop out a lot of the sky and trees as well; if I were to shoot, I would use a wider aperture to throw those out of focus.
Your subject is pretty well in the centre of the image, and compositionally, this is usually not a strong approach. Think about the "rule of thirds" when composing. I've overlaid a grid on your image and done a crop to place the subjects on / near the thirds and placed a couple of the main parts of the image near the nodes where the lines intersect.

As I have not any idea of post processing I don't know what you are talking about when you said "I applied a vignette, can you kindly explain what is a vignette.I neither have any idea of how to interpret an histogram or to correct the colors tt appears in the original shooting, but thanks a lot grumpy driver.
Cordially,
Catalina
I also find your straight out of the camera image a bit flat. The whites are close to being blown out, but the blacks are too gray. I've also applied a vignette to pull the viewer's eyes more into the frame.
The famous photographer, Robert Capa said something along the lines of "if your image is not good enough, you're not close enough". I frequently use this advice when I am out shooting.