We've already talked about Simple and Unexpected as 2 key principles for why ideas stick. Now we cover 2 more:
1. Concrete - use of simple, vivid language. The opposite of abstraction.
2. Credible - use of internal or external authority to make your message more believable.
Easy visualized nouns ("bicycle" or "avocado") are easier to remember than abstract ones ("justice" or "personality").
Use personas to make your customer more concrete.
Have someone that knows the intended recipient spread your message for you. We believe our family and friends.
Use authorities--experts, aspirational figures, or "anti-authorities" (people who truly embody the essence of the message)
Internal credibility comes from relevant details, statistics (using the human-scale principle: "in other words, you would have to drink 200 glasses of OJ to get the same Vitamin C"), the Sinatra test (if you can make it here, you can make it anywhere).
The last point re: internal credibility--I've seen this at work in a few different situations. At McKinsey, I noticed that the most effective folks were the ones who had a phenomenal memory for details. They could surface extremely specific, relevant details at the right moment. Lars, one of my EMs, also told me that you should have the numbers in your model at the tip of your fingertips. This also goes to the point of statistics. People--especially analytical people in business--tend to be persuaded by numbers and quantification. Finally, regarding the Sinatra effect--we used this at Yodlee. We would say, "Our security has been audited by the top 10 banks, companies like Merrill Lynch, American Express, and Bank of America. Don't you think we could pass your security audit process?"