6 insights from self-made millionaires that will change the way you think about money

Building wealth has more to do with your mindset than you may think.

According to Grant Cardone, who went from broke to seven figures by following a few straight-forward steps, the first thing to do is to commit, mentally, to the idea of getting rich: "The biggest mistake is to think becoming a millionaire is impossible. The first thing you have to do is decide to become a millionaire, multimillionaire, or billionaire if you want."

To help you start thinking like the wealthy, CNBC rounded up pearls of wisdom from self-made millionaires and billionaires that may change the way you look at money.

"The best investment you will ever make is in yourself." —Grant Cardone

It's advice that his mom gave him. "It's a-no lose deal," she told Cardone. "It will always give you a return. Nobody can take it from you. It's yours.'"

Struggling to make ends meet with his job at a car dealership, the then 25-year-old Cardone put his mom's advice into effect. "Even though I hated the job, I decided I would throw myself into my sales job 100 percent," he writes of his younger self in "Be Obsessed Or Be Average."

He watched sales training videos while he ate breakfast, listened to self-improvement tapes during his drive to work and was often the first employee to show up and the last to leave. Cardone started to see results. He went from making $3,000 a month to $6,000 a month in his commission-based job. By 30, the entrepreneur had notched his first million.

"Regardless of the size of your paycheck, you probably already make enough money to become rich." —David Bach

"How much you earn has almost no bearing on whether or not you can and will build wealth," writes self-made millionaire David Bach in "The Automatic Millionaire." It's not about how money much you make, he says, but how much you keep.

The good news is that you don't have to earn six figures to start saving and investing — anyone can find ways to set aside a portion of their income. The philosophy is one of paying yourself first. The key is to start as early as possible, in order to reap the full benefits of compound interest.

"You can have it all." —Steve Siebold

You don't have to choose between having a great family and being rich, says self-made millionaire Steve Siebold. As he writes in "How Rich People Think," "The most common middle-class belief I have encountered … is the mistaken idea that you have to choose between world-class success and a happy family life."

Just look at the five richest men in the world, who are all fathers. The belief that wealth must come at the expense of family time is a "cop out," Siebold says: "If you love your family, get rich and give them more of your time, plus opportunities only money can buy. Figure out a way to be more efficient with your time so you have plenty to spend with them while you're doing it."

"It's pretty easy to get well-to-do slowly. But it's not easy to get rich quick." —Warren Buffett

The golden rule of investing is to think long term. The most successful investors, like self-made billionaire Warren Buffett, use the buy-and-hold strategy.

"The money is made in investments by investing," Buffett tells CNBC, "and by owning good companies for long periods of time. If they buy good companies, buy them over time, they're going to do fine 10, 20, 30 years from now."

"There is nothing more important to securing your financial future than getting paid what you are worth." —Grant Sabateir

In fact, "the number one thing that will dictate your future earning potential and get you to $1 million the fastest is how much money you are being paid today," says Grant Sabateir, who went from having $2.26 in his bank account to $1 million in just five years.

"Unfortunately, you probably aren't being paid what you are worth."

You can't sit around and expect a raise or bonus to fall in your lap. You have to ask for what you want. And there's a right and a wrong way to go about asking for a raise. Sabateir recommends looking at the salary range for someone with your level of experience in your industry, which will help you understand what you're worth.

Then, take that information to your boss and emphasize what you bring to the company. Remember, "it doesn't hurt to ask," he tells CNBC. "A lot of people are ultimately afraid that people are going to say no, and so they undervalue themselves and they undervalue their services."

"In most cases, your net worth mirrors the level of your closest friends." —Steve Siebold

Who you hang out with matters. It could even affect your net worth, Siebold writes on Business Insider.

As he explains in "How Rich People Think," "Successful people generally agree that consciousness is contagious, and that exposure to people who are more successful has the potential to expand your thinking and catapult your income. We become like the people we associate with, and that's why winners are attracted to winners."

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