I was convinced I had created a billion-dollar idea. It had all the attributes of a great concept. It was something no one had created before, I validated the need for it, and it was in a huge market. I just had one big problem: I didn't have the time to run the company.

I told a few close friends about my idea, and one of them recommended someone to lead the operation. I had never met the person they recommended, but over one coffee meeting, I was convinced he was the right candidate for the top spot. So I became an investor, and he ran the company.

I trusted him even though I'd only known him for 45 minutes. You can probably guess the rest of the story. The company made no real progress for six months. Then, the unthinkable happened. After an investigation, I found out he was lying about almost everything he was running. When he told the board that we had large enterprise customers signed up, it was all a complete fabrication.

I learned that lesson the hard way. So when I read Malcolm Gladwell's new book called Talking to Strangers: What We Should Know about the People We Don't Know it reminded me of how we should approach others with caution and confidence.

Malcolm Gladwell, you may remember, is the bestselling author who made social psychology cool again with books such as The Tipping Point and David & Goliath. Love him or hate him--and people do both--Gladwell has cemented his reputation as an explainer of contemporary culture.

In his new book, Gladwell claims we can't talk to each other properly because we trust each other too much. He calls it "default to truth." 

Basically, we assume the best about others from the beginning, and not everyone has good intentions, nor is the world always a truthful place. "Why can't we tell when the stranger in front of us is lying to our face?" Gladwell asks. Because we assume the person is telling the truth. And that assumption can get us into trouble.

Gladwell's book is pretty bleak, honestly. He worries that nobody is really telling the truth. But on that point, I have to disagree with him. The fact is that most of us are generally honest people. That's what makes it so hard to know who we shouldn't believe. We can't go around suspiciously fact-checking everyone we meet. But we do need to balance confidence with caution.

We don't know who to believe and who to question. So we tend to trust everyone equally, and then we get ourselves into trouble. The number one communication skill we lack is this: discernment, or the ability to make good judgments about others. To be discerning, you don't have to be suspicious or negative. But you do have to think critically about the people and situations you approach every day.

So how can you build discernment as a communicator and a leader? 

1. It takes commitment and practice. 

Like any other leadership trait, discernment is a learned skill. You aren't born a discerning person; you become one through practice. So, make a conscious effort to develop your eye for repeated behavior patterns that should send up a red flag.

For example, red flags could be people who are in a huge hurry, those who lavish you with compliments, and businesses with high turnover should get a second or third look before you decide to trust them.

2. Don't confuse information with analytics. 

The world is awash in data. What we're missing is the ability to sift through that data and turn it into meaningful, actionable content. So just because you know a lot about a prospective business partner, employee, or client doesn't mean you have the right information to determine if they're trustworthy.

3. Check your gut.

If you are hesitating to trust someone, there's probably a good reason your emotions have identified something before your intellect did. Take your time. Do your research. Check in with other people. Better to take an extra week to be sure than to get stuck in a draining business relationship for years. ​