When I started compositing, colour correction seemed like a black art. I would push and pull different controls until I would eventually get something that looked somewhat like what I wanted. When I had spare time, I would open other artists’ scripts and I’d marvel at how they would colour correct a shot. Every artists' technique was different - some would exclusively use curves. Others would use levels/histograms, while others would use numeric inputs. Looking at other artists' scripts would allow me to undertand their technique, but I was still clueless about their thought process - about why they did what they did.
Even now, whenever I submit a shot for review, I receive feedback about a necessary colour correction. There is definitely a certain level of subjectivity to colour correction: supervisors often have a different idea than I on how a shot should look. However, I’m now usually much closer to the target than I used to be, and it only takes one or two iterations before everyone is satisfied.
These books contain great advice about how to approach colour correction. Wright and Brinkmanns’ books are software independent, while Christiansen’s book is specific to After Effects.
The Art and Science of Digital Compositing