Dale Carnegie's principles from "How to Win Friends and Influence People" provide guidance on becoming a friendlier person, winning people over to your way of thinking, and being a leader. Some key recommendations include don't criticize others, give sincere appreciation, make others feel important, respect others' opinions, see things from their perspective, appeal to their nobler motives, begin with praise, and use encouragement. The overall message is that treating people well, making them feel heard and important, and appealing to their better nature are effective strategies for influencing them.