What is it?
People overestimate the knowledge of the other, because they think everyone knows what they know. This is called the curse knowledge. Technology suppliers are experts on their technology, while their potential customers are not. The curse of knowledge also applies for example to designers: they sometimes make products that are too difficult for users.
Make your story understandable and concrete
Use examples to explain your story
Level or the other you follow, but keep in mind
that people sometimes don't want to be.
Involve a third person in the conversation that is not an expert. This gives you an excuse to explain things simply without underestimating the other.
Remember that your story will be retold to non-experts.
Read more on the Curse of knowledge
Blog from Chip Heath en Dan Heath about the curse of knowledge on Harvard Business review
Colin Camerer, George Loewenstein & Martin Weber (1989). The curse of knowledge in economic settings: An experimental analysis. Journal of political Economy, 97(5), 1232-1254. Link
Boaz Keysar (1994). The illusory transparency of intention: Linguistic perspective taking in text. Cognitive Psychology, 26(2), 165-208. Link