1. Lots of movement. Show what the runway or static images can't show.
2. Mirrored frames. This is a favorite effect of almost all fashion videos.
3. Some kind of electronic or industrial soundtrack. Neutral, easy to create and loop.
Missoni's Spring 2011 campaign video exemplifies the fashion video formula to a T. The clip features members of the Missoni family and friends (including Leighton Meester). Not the most impressive video, but it's the first time I'm actually liking the techno-tribal prints they designed.