The first thing I do with any shot is try to get on paper as quick as I can what I am seeing in my mind's eye. It can be a lot more difficult than you think. The audio clip (especially this one) tends to zip by so listening to it over and over and over again is imperative to find the key moments in the voice of the performer. Here are some of my thumbnails sketches based on where I wanted to go with the shot.
Once I had those ideas on paper where I could see them and study them, the next thing I did was act it out. Again, this is not my technique, rather I'm just using someone else's proven method. Anyway, not only will I record myself, but I take it one step further and add a time frame stamp and then go even one step further and import the video clip into Flash (or any similar 2D app.) and literally make visual notes on my own performance. Now some may say this is a little overkill, but for me, it helps a ton. Very quickly I have resolved many of the issues in my character's performance such as the timing, the posing, and the spacing that I could waste hours trying to figure out on my own. Again, if I'm the animator I have to become the character. I'm not cheating by using reference video, I'm becoming the character!
Finally, the animation basically reflects my performance. While I used thumbnail drawings and reference video to get me started, you can clearly see that I only used it as a guide. To me the most fun part in animating is trying to find those little moments where you can exaggerate the character beyond anything you could do in reality. That's really the magic of the whole process for me. Anyway, I hope someone out there can take these ideas (again, that I have borrowed) and use them to make their own animation even better!