Entrepreneurs, in my mind, aren’t just founders of for-profit business. It’s anyone who comes up an idea and turns it into something real, who translates a passion into a project.

As the mom of two entrepreneurial sons, I’ve found that of all the parenting advice out there, the most important ones are about teaching kids to be bold enough to try new things. But how do you do that?

When writing my book, “Raising an Entrepreneur,” I asked 70 parents who raised highly successful adults about the most extreme things they did that helped make their kids brave and confident:

1. They taught their kids to always be curious, and never fearful.
Sometimes, this means letting kids break rules.

Tania Yuki is the founder and CEO of Shareablee, a company that analyzes the impact of businesses’ social media platforms.

Tania developed her fearlessness and willingness to experiment when she was just four years old. She recalls shopping with her dad at a luxury gift store. Despite the “NO TOUCHING” sign, she touched nearly everything.

A salesclerk saw and snatched something out of her hand. For a minute, Tania thought she was in trouble. But her dad stepped in and said, “She’s just curious. If she breaks anything, I’ll pay for it!”

“At that moment, I knew my parents would always trust me,” Tania told me. “They never had any reason to discourage anything I was curious about. I never felt I would suffer consequences for being curious.”

2. They gave their kids independence at a very, very young age.
The parents I interviewed all agreed: The sooner kids are given big responsibilities, the more confident and independent they’ll become.

Michael Skolnik is the founding partner of The Soze Agency, a company that creates corporate campaigns. He developed his love for theater at age 14, and wrote letters to 50 Broadway producers asking to be an intern. He got one yes, from Blue Man Group, based in New York City.

His parents worked full-time and couldn’t drive him from their home in Westchester county to NYC every day; but they had friends with an empty apartment in the city, so they let him live there by himself that summer.

“I don’t know if that much freedom and independence at such a young age would work for everyone, but it did for me,” Michael said. “Their trust in me let me mature a lot earlier than my peers.”

3. They didn’t pick their kids’ passions.
It’s not always easy to trust in outcomes we can’t yet see. But these parents all trusted their kids to make choices about how they spent their time.

Eric Ryan is the co-founder of Method Products, a $100 million company that makes cleaning products. Growing up, his passion was sailing.

“I wasn’t a good student, but I loved sailing and worked hard at that. I sailed competitively from fourth grade through college,” he said. “My dad was always there to support me at regattas, even though he didn’t know anything about sailing.”

Eric, like many of the entrepreneurs I met, chose a passion that his parents might not have picked for him.

His mom told me: “My husband and I had a list of things we wanted them to know how to do — ski, ice skate — but then they chose what they were interested in.”

4. They shared their own struggles.
Many people think that successful adults had thing easy as kids. But oftentimes, people become successful because they learned how to deal with failure.

Paige Mycoskie is one of the richest self-made women in the U.S., through her clothing brand Aviator Nation. Her mom Pam told me that Paige’s resilience came from watching her go through her own struggles.

“I found out I had high cholesterol, and I had to change my diet. I wrote a book with recipes for how to cook with less fat,” she said. “I didn’t know anything about writing a book or about the publishing industry.”

Another parent might have hidden how much she was struggling, not wanting to upset her children. But Pam chose to share her experience with them. Her kids learned that everyone has to deal with problems —and that, with grit and determination, problems can be tackled head on.