Be a friend to your rivals to gain valuable information, or have others spy for you. In social situations, ask indirect questions to find out their intentions and weaknesses.

Collect valuable information on people to destroy them or win them over. For example, you may need to win over someone at work to get more opportunities or a teacher to get the referral you need. Or if you have a rival at work or school, and it's better to know what they are plotting to get ahead of it. In our world, this law applies to businesses as well as people. If you think about it, the apps we like to use are free for a reason; to pose as a useful tool to collect information and sell you products.

Most people are distrustful and will not share sensitive information openly. One way is to engage someone in friendly conversation and act interested in them so that they reveal things about themselves. Or you can talk about something that seemingly doesn't have to do with them, just to see the reaction they get. But this type of tactic needs to be subtle or people will catch on and stop sharing.

I was in Asia, traveling for work with a few co-workers at a new company. The four of us were on a long car ride going back to the hotel and everyone was tired from the day. One of my coworkers who was the most outgoing started asking me questions for all to hear. We got into what seemed like a standard introductory conversation.

She led with a couple of typical questions.

"Where were you before this?""How many years were you there?"

I answered those. And instead of sharing anything in return, she continued to ask more questions. The questions became more probing.

"What did you do before that?""Where did you go to school and what did you study?""Where was your first job?"

At that point, it no longer felt like a friendly getting-to-know-you conversation, but more like an interrogation. Another coworker who was listening jokingly pointed out it sounded like a job interview. I chuckled but purposely deflected the rest of her questions. For example, when she asked me where my first job was, the implication was where I got started in the industry. I deflected by telling her about my first job in high school; I was a magician's assistant which I knew would be way more interesting to everyone else. I could tell my coworker did not get any satisfaction.

In order to size me up, she was too eager to learn everything about me in one conversation. If only she gathered the information from different conversations or perhaps from other sources, she would have found out everything without being so obvious.