Customize only one folder

You can do that by right clicking the folder then properties, customize, change icon.

Thank you for your answer, but his way I can't get my objetive. The problem with simply changing the icon is that you can't really see a preview of what's inside the folder, as Windows does with default icon folder. I would like to change the colour of the icon folder, keeping the preview of what's inside the folder. And I would like to have different colours for different folders.

You can't change live folders for individual folders.