If you remember nothing else about designing a TV – or Radio – spot, remember this:
The core message of your ad matters more than how well it is written. The core message of your ad matters more than how well it is produced. The core message of your ad matters more than the spokesperson who delivers it for you. The core message of your ad matters more than your choice of media. The core message of your ad matters more than the target it reaches.
From Advertising guru Roy Williams.
More here.