Like anything else, color correction has its own fundamental principles and rules.
And like anyone else, if you don’t know the rules you wind up with lots of questions:
Do you adjust the black levels first or the while levels?
How do you correct skin tone?
How do you completely change the color of something in the scene?
I found this 20 minute video from Larry Jordan particularly informative and useful. (For his written article on the same subject go here.)