How to win friends and influence people

"How to Win Friends and Influence People", is a self-help book written by Dale Carnegie, published in 1936. Over 30 million copies have been sold worldwide, making it one of the best-selling books of all time Carnegie had been conducting business education courses in New York since 1912 and went on to become one of the most celebrated trainers in the arts of business and inter-personal communication.

But what lessons can modern day marketers learn?