Have you talked with a customer, a colleague, an employee, or a friend, and wished you could get them to open up and tell you what they were really thinking? While you can't--and shouldn't--spike someone's coffee with truth serum, you can greatly improve your chances of learning the truth by using a few simple techniques honed by an investigative journalist over years of interviews. These techniques have nothing to do with manipulation and everything to do with emotional intelligence and they can help you in almost any interaction.

That advice comes from an unnamed investigative journalist interviewed by Lindsey Ellefson for Lifehacker. I can't vouch for the journalist since he chose to remain anonymous. But I can vouch for the validity of his advice. I've used these techniques myself in thousands of interviews over the years. People have mostly opened up to me pretty quickly--often more than the PR person chaperoning the interview wanted them to.

You can find all the journalist's tips here. These are my two favorites of them, along with one of my own.

1. Start slow.

Getting someone to open up to you is not about conversational tactics and all about being open and kind yourself. Don't hurry to pressure the other person to tell you anything before they're ready. Don't jump straight to the information you really want to know. Keep the conversation light at first. Tell them a little something about yourself so they can start getting to know you.

It should go without saying that you won't use anything they tell you to gain advantage over this person later on. Remember that your career and your reputation will last a lot longer than one interaction. You may not care what this person thinks of you, but they're likely to relate their experience to someone whose opinion does matter. So once you've earned someone's trust, make sure that you really do deserve it, and make sure you keep it.

2. Be empathetic.

As someone starts to open up, do your best to see the situation from their point of view and to express that empathy. Say something like "That must have been very challenging for you," or (if it's something good) "You must have been so pleased when that happened." If you want to tell them you've had a similar experience, it's fine to do that perhaps once in a conversation, but be careful not to sound like you're trying to one-up them--and be especially careful to keep the focus on them, not on you. Let them do most of the talking. Make sure to make frequent (but not constant) eye contact, nod sympathetically, and give small verbal cues that you're listening and engaged. Be patient! The longer someone talks to you, the likelier they are to tell you what you want to know.

3. Make talking to you a pleasure.

I can't count the number of times someone I've just interviewed has said something like "I'd be happy to have another conversation sometime--it was fun talking with you." That's always great to hear, because it means you can come back later on and the person will happily share more information. This is one more reason to maintain someone's trust once you've gained it.

There's a small but growing group of Inc.com readers who get a daily text from me with a self-care or motivational tip or micro-challenge. Often, they text me back and we wind up in an ongoing conversation. (Interested in joining? You can learn more here.) Many are successful entrepreneurs or executives, and they tell me that building trusting relationships like these and maintaining them over time is essential to their success.

So think for the long term. Once you've established trust with someone, they can become an ongoing resource and an ally who can help you for years into the future. And that's a very valuable asset for both your business and your career.