Mark Cuban knows what sets successful people apart from the crowd.

Cuban, 66, is both a self-made billionaire and a longtime startup investor who's listened to many business pitches in more than a decade on ABC's "Shark Tank" and mentored dozens of entrepreneurs he's helped fund.

The core traits and strategies that make people successful haven't changed since Cuban first got started, he tells CNBC Make It: "The skills you need for a job today, 10 years from now, 100 years from now, are always the same."

You could land a coveted job, negotiate like a "Shark Tank" investor or launch a lucrative side hustle by mastering a specific handful of hard and soft skills, says Cuban.

Here are three pieces of advice from the billionaire:

Focus on 3 soft skills to land a job

Whenever the job market seems daunting, you can always fall back on the same three soft skills, Cuban says: agility, curiosity and adaptability.

"I can pretend that I'm going to be able to predict where AI's going and the exact impact on the job market, but I'd be lying," he says. "I have no idea. But I do know that I am going to pay attention, and be agile, and be curious, and be able to adapt."

Recruiters are especially seeking adaptability right now: The trait was deemed "mission-critical for both people and organizations" by a LinkedIn blog published in February. Highly adaptable people are typically capable of picking up new skills, applying old skills in new ways or simply feeling confident while navigating rapidly changing social norms.

"Adaptability is the best way to have agency right now," says Aneesh Raman, LinedIn's chief economic opportunity officer. "At the core of managing change is building that muscle of adaptability." 

Pick up these 2 crucial negotiation skills

Whether you're asking for a promotion or arguing with your partner about where to grab takeout, being a good negotiator can help you get what you want.

You won't win by speaking the loudest or having the most detailed argument. Instead, the best dealmakers do two things when negotiating, Cuban says: "One: They're patient because they know what they're trying to accomplish. Two: They don't try to win every deal point. It's OK to give something in order to get the deal done."

On "Shark Tank," Cuban often sits in silence while his fellow panelists share their opinions and questions with the business owners seeking funding. The tactic gives him more time to think and build on his co-stars' insights, he's said.

″There will be times when someone walks in on 'Shark Tank' and [I think]: 'There's no way I'm interested.' [or] I don't have quite all the data that I need to make a decision,'" Cuban said in an interview with former FBI hostage negotiator Chris Voss last year. "When I listen to the other Sharks, they're going to tell me if I have any competition financially to do a deal. They're going to teach me things, potentially, about that industry ... about the person."

Turn up-and-coming trends into side hustles

Cuban became a millionaire by creating a software company — called MicroSolutions — and selling it in 1990, around the time personal computers were becoming popular in American homes. Similarly, he reached billionaire status by selling his audio streaming service Broadcast.com to Yahoo in 1999, ahead of the modern-day content-streaming boom.

AI is today's version of those trends, says Cuban. If he were a teenager again today, he says, he'd harness language models like OpenAI's ChatGPT or Google's Gemini to make some extra cash. He'd launch his side hustle in just three steps:

1. Learn how to write prompts for AI chatbots.
2. Teach his friends how to use those prompts for their school papers.
3. Take that same skillset to businesses, "particularly small- to medium-sized businesses that don't understand AI yet."

"Doesn't matter if I'm 16," says Cuban. "I'd be teaching [businesses] as well."

AI prompt engineering is a high-paying job that doesn't require a college degree: The average pay for AI tutors starts at about $30,000 per year, and full-time AI prompt engineers can make up to $129,500, according to job board platform ZipRecruiter.

Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."

Want to earn more money at work? Take CNBC's new online course How to Negotiate a Higher Salary. Expert instructors will teach you the skills you need to get a bigger paycheck, including how to prepare and build your confidence, what to do and say, and how to craft a counteroffer. Start today and use coupon code EARLYBIRD for an introductory discount of 50% off through November 26, 2024.