Shark Tank judge Mark Cuban’s 4 rules to become a millionaire

File image of Mark Cuban.

Billionaire investor Mark Cuban decided to strike out on his own after being sacked from a job. Today, he is worth over $4 billion, owns the Dallas Mavericks basketball team and has investments in dozens of startups.

Cuban has advice to offer to those who want to start their own lucrative ventures. In an interview with GQ, he detailed four rules that people must follow to become millionaires.

"If you want to be a millionaire, you can do it, but there's a couple things you have to be able to accomplish," Cuban said.

The first, he said, was finding something you are good at and then perfecting it.

The second rule is learning how to sell whatever service or product you have mastered.

"Whatever it is that you're creating, you have to be able to sell because you don't want to be in a position where you're dependent on other people," the investor told GQ.

Third, he said, one must always be learning new things, given the ever-changing nature of business.

Fourth, Cuban said, you must "know your s***" better than anyone else

"That's when it's time to start a company," he added. "Then you can start to control your own destiny."

Cuban is best known for appearing for over 10 years on the American reality tv show Shark Tank. During his time on the programme, he invested $20 million in 85 startups, according to CNBC.

Cuban's wealth-building journey began with the sale of his technology startup MicroSolutions in 1990.

He went on to set up internet radio company Broadcast.com with his fellow Indiana University student Todd Wagner in 1995, Forbes magazine reported. Four years later, they sold it to Yahoo for $5.7 billion. It was the most expensive of Yahoo's acquisitions.