Put your best stuff up front.

This comes from that casting office perspective that I mentioned earlier.  Just like any presentation, consider your audience first. In this case, the "audience" is a busy casting office, and, specifically, a poor chap who has been sitting in font of his monitor watching hundreds of faces talking at him for many hours.

Casting reality check:  Producers like Oprah don't sit through all the submission; all videos are screened and only the most promising  make it to the producer at all!