6 blue-collar millionaires all made this one mental shift

Steve Hightower in front of his 11,000 square foot house.
Photo courtesy Hightowers Petroleum

Success often comes from determination and a deeply held conviction in your own ability.

For these six self-made, blue-collar millionaires, the path to wealth may have been different, but the mentality was the same: They all believed strongly in themselves. They felt certain that eventually, with enough time and hard work, they were capable of building successful companies.

And they were.

Dru Riess and Ray Salinas turned an old, dirty printing press in a barn into a $25 million business

These guys succeeded by taking over a dying business in a Texas barn

"I firmly believe that not anybody can be a millionaire. You gotta really, really want it," says Riess.

"There are a lot of people that, especially in this generation, just expect things to be given to them," he says. "You've got to put everything aside, people doubting you, people looking at you saying, you know, 'That's not a good idea,' and just ... grind through that. Push through it.

Steve Hightower went from cleaning toilets to running a $350 million oil business

This Ohio custodian followed his passion and became a CEO

"When people ask me, 'Would I ever have imagined I would be where I am today?' Absolutely," Hightower says. "Because if you don't think that you can be great, you'll never be great. And I knew that I was gonna be great a long, long time ago."

Rick and Bunny Lightsey transformed Rick's father's small alligator business into a million-dollar operation

Florida couple makes millions by innovating alligator trapping business

"I think sometimes people don't succeed because it's not fast enough. You know, Ricky and I went through a lot of different things. You know, we're in our 60's. And, you know, we're finally feeling some real success," says Bunny Lightsey. "It's persistence of doing what you like."

Steven Humble turned a fascination with hidden doors and secret passageways into a million-dollar business

This engineer quit his day job to build 'secret doors'

"I had designed this product that made my boss a ton of money and I feel like I am just stuck in this cubicle," says Humble. "I thought, 'Surely I can do that. I have that skill set.'"

Bruce Schindler grew up on food stamps and became a millionaire excavating mammoth tusks in Alaska

This 'Mammoth Hunter' turned his hobby into a business—and a fortune

"Don't be afraid to make a profit," Schindler says. "So often I see people who are starting out, selling the things they make, and they don't value what they made because they made it with their own hand. But that thing they made with their own hand is more valuable than any label that's out there."

Mike Vetter started out flipping burgers at Burger King and became a self-made millionaire building custom movie cars and concept cars

One man made millions switching from fast food to fast cars

"There's not really any trick," says Vetter. "I'm living proof that everyone of us can have anything that they want. You simply set a target and work towards it. It may not arrive as fast as you hoped, but if you keep working at it, it will come."

"Blue Collar Millionaires" airs Wednesdays at 10 p.m. ET.