The Graph Editor

A lot of people are asking about the magic of the graph editor. Some people live and breathe it, others use it for clean up. I'm more of a clean-up guy. If pops show up in my animation, then I check the graph, if the rig is light enough for real time playback, I adjust the curves to tweak the timing, etc. but I'm not the person who breaks the tangents and weighs/unweighs them and all that jazz. I know a few who do and others who don't.
But I believe one thing, the graph editor is not a magic tool. You won't get super polished animation just by using it. You need to know why of course. It's just another tool that lets you tweak your keys and curves.

Victor Navone has written a great tutorial on Splines, I highly recommend both Part 1 and Part 2.