The Definitive Guide to Business with Marcus Lemonis

Marcus Lemonis reveals the 4 most common mistakes that entrepreneurs make

Every entrepreneur makes mistakes along the way. But according to investor and serial entrepreneur Marcus Lemonis, there are a few common missteps that are difficult to overcome.

Lemonis, the CEO of Camping World and host of CNBC's "The Profit," shared some of the biggest mistakes that entrepreneurs make and would be wise to avoid.

1. Thinking you know it all

For nearly all entrepreneurs, business is personal.

But if someone has better advice than you, you have to be willing to separate your own feelings of attachment and listen, the entrepreneur said.

"They think that every idea that comes out of their head is a good one," Lemonis said.

Not listening to others can hinder your own success, he added.

2. Not recognizing your team

You can't build a great company alone. Taking the time to recognize the hard work of your team is crucial, according to Lemonis.

It's a common but detrimental error when entrepreneurs "don't put enough credence into the people that are around them," he said.

In fact, sometimes your team will have better ideas than a business leader, he added.

3. Not knowing your numbers

Lemonis said he often finds that even the most sophisticated business owner doesn't really know their numbers.

The most important numbers entrepreneurs should know are their annual sales revenue, gross profit margins and expenses as a percentage of gross profit margin, he said.

"No one person that runs a business or owns a business is too busy to know the ins and outs of their business," he noted.

4. Ignoring feedback

Sometimes entrepreneurs love their company so much, they ignore the lukewarm or negative feedback others are giving them.

"I like to romanticize businesses, and I fall in love with them," Lemonis said. "But oftentimes, I see people fall in love with their idea. They've been reinventing the 8-track cassette tape for 12 years, and they put a lot of time and money in it. And it's still a bad idea."

The investor said entrepreneurs should solicit feedback from potential users, and listen to it.

"The best litmus tests for early ideas are people's reactions to things," he said.