I don't feel like I'm at a skill level where I should be teaching anyone about animation :P
But when I'm working on a cinematic, the first thing I do is focus on the key poses for the different stages.
Then while blocking out the rough movement, I get the animation working in-game to get a feel for what it will look like when finished.
Then I spend the rest of the time I have available on getting the stages to flow together, and general polish.