Ever notice how a condensed version of something isn’t quite as powerful as the full version? A trailer is no substitute for the full film. Cliff’s Notes don’t even come close to immersing yourself in a good book. A billboard created from a solid TV spot or decent print ad is usually completely ignorable.
When you’re creating an ad campaign in multiple media, try developing the outdoor first. Make it solid. Make it powerful. Make it the essence of what you’re trying to accomplish. Then expand upon that concept in other media.