Came across this ad for O&M from David Ogilvy. I think it is from the 60s but some of the lessons are still pertinent today. If you click on it you should be able to blow it up big enough to read but here are my choice quotes
A promise is not a claim, or a theme, or a slogan. It is a benefit for the consumer.
It takes a BIG IDEA to jolt the consumer out of his indifference – to make him notice your advertising, remember it and take action.
Big ideas are usually simple ideas.
Nobody was ever bored into buying a product.
The pursuit of creative awards seduces creative people from the pursuit of sales.
Most advertising campaigns are too complicated. They reflect a long list of marketing objectives.