Though he took cat naps throughout the day, Tesla also claimed he never slept more than 2 hours. Once, he stopped eating solid foods, opting instead f...

This is the most important principle in Carnegie's book. It's about taking the time to learn about other people's interests and concerns. When you show genuine interest in someone, they're more likely to feel like you're paying attention to them and that you value their company.

• If you find it challenging to move beyond small-talk, you can ask a more personal question like, "What's one thing that I don't know about you?" or "If you could travel anywhere in the world, where would you go?"
• Use info from social media as a conversation starte...