In practical terms, this means that there must be one, central message. In the 1980s, the US Army developed a concept called "Commander’s Intent". This means whenever an order is given, there is a crisp, plain-talk statement included which specifies the order’s goal. This has been very effective. Try to think in terms of what you want the customer to ask, rather than what information you want ton convey. Images and "fun facts" will also be more powerful than a regurgitating advertising "message". Make an effort to find ways to make your product emotionally appealing.
Some of these concepts will doubtless be familiar, but Chip and Dan Heath present them together in a coherent structure, with specific examples and clear recommendations. This is a very useful book.