Watching a video will never be enough in my opinion. It can give you a good idea of what's coming, but until you jump in, you will never know how you will react to certain mechanics.

My tactic? Get in there and practice ^^

Die as many times as needed for you to get a feeling of the fight and how you will react to certain mechanics. After a while, it'll become muscle memory and you'll pretty much be able to do the fight in your sleep. xD