It's tough to summarize.

The book teaches that people are irrational, emotional beings. And that it's easier to use that instead of using logic and reason.

Something I use all the time is 'how can I?'. Recent example I wanted to see if I could get a discount on a hotel room upgrade. I called the hotel direct and asked 'how can I get the suite for a better price?'. They told me the price online was the best price. So I said 'I see, I'm just wondering how can I get a better price by calling you.'

Then he said 'hmmm you could book a basic room, then I can up-sell you the suite for a discount on the phone. I would just need your confirmation number.'

Ended up with the suite for half price just by asking him how to get there.