Color grading is not only an important part of filmmaking, it's an entire career in itself. There's a lot to know, but getting the basics understood shouldn't be as daunting as it might be. In this video, get a color grading 101 from Film Riot.
I used to love post-production of photography and video. In fact, it might have been my favorite part of the whole process of creating images, moving or otherwise. But, somewhere along the line, I fell out of love with almost all of it and started outsourcing retouching. However, there is one part that I don't farm out and still enjoy: color grading.
My first real experience with color grading was not video, but stills. I was shooting commercial imagery for a brand that wanted to use the shots for an advertising campaign. As part of the brief, they asked me to make the shots seem as if they were a screengrab from a film, which I was more than interested in doing. I spent far too long trying to recreate the looks I had enjoyed in films and series, and apart from crushing the blacks a little, the bulk of the post-production was color grading. Since then, and to this day, I love playing with colors to complement an image or video, though there is a lot to learn.
This video acts as a superb introduction to the fundamentals of color grading for video and it's one that's not only well worth a watch, but worth bookmarking too.