Are you making this mistake in business? Learn from a startup pro for ultimate success

Confidence is crucial when you're diving into the business world, but there's a pitfall you need to avoid: overconfidence. 

Successful entrepreneur Alexa von Tobel, who sold her startup for a staggering £375 million, has a vital lesson for all budding business moguls like you, 

Von Tobel, the brain behind the online financial advisor platform LearnVest, sat down with CNBC Make It to share the top lesson she learned during her journey. It's simple but often overlooked: Never fall into the trap of thinking everything is perfect. Von Tobel explains that the most triumphant entrepreneurs she's encountered maintain a careful balance between confidence and what she terms "healthy paranoia."

The founder's own experience supports this notion. When she launched LearnVest amidst the 2008 financial crisis, the initial success didn't lead her astray. Despite thousands of excited users flooding the platform on the launch day, she remained level-headed. Von Tobel stresses that executing a business idea with true success is challenging, and one must stay vigilant and seize momentum for lasting triumph.

Research shows that overconfidence tends to plague entrepreneurs more than the average person. This is hardly surprising, given the high stakes and tough odds new businesses face. However, this overconfidence can prove detrimental, especially when it leads to risky decisions that backfire.

Von Tobel's strategy was the opposite. Instead of getting swept up in early victories, she charted a path of steady growth. This method paid off, as LearnVest reached a remarkable 1.5 million users within seven years. Eventually, she clinched a sale to Northwestern Mutual for a staggering £375 million in 2015.

So, what's her advice to you? Nurture a "healthy paranoia." This doesn't mean living in constant fear but rather making well-thought-out decisions and avoiding the trap of overconfidence. 

Von Tobel believes that by committing to consistent hard work and smart choices over a decade, you too can build a truly successful venture. Remember, staying humble while confident might just be the key to your future success.