Once I stopped being so stiff legged and began to hop around from edge to edge, use my core and upper body to shift my weight quicker, and make my body more "liquid," I noticed an extremely dramatic improvement in my riding, especially at high speeds and on steeps.
It is important to ride within your abilities, so working on these things at a comfortable pace is crucial to staying safe. Don't worry, if you have a desire to improve and the willpower, you will get better in time.
In regards to that video, I have tried listening to my iPod on the hill and find it distracting and puts me in a bubble. I do like to listen to it on the lift, however. To each their own.