When it comes to earning more money and growing your wealth, sometimes all it takes is establishing smart habits and making small lifestyle changes.

"Success is a learnable skill," writes T. Harv Eker in his book "Secrets of the Millionaire Mind." "If you want to be a great golfer, you can learn how to do it. If you want to be a great piano player, you can learn how to do it ... If you want to be rich, you can learn how to do it."

If you want to learn how to get rich — how to grow and master your money — consider these nine lifestyle changes:

Previous reporting by Kathleen Elkins.

Start hanging out with people you admire

Andrew Carnegie, who started with nothing before becoming the richest man in the country, credits all of his riches to one principle: the Master Mind.

The idea is that you surround yourself with talented people who share your vision because the alignment of several smart and creative minds is exponentially more powerful than just one.

Plus, we become like the people we associate with, which is why the rich tend to associate with others who are rich.

"In most cases, your net worth mirrors the level of your closest friends," explains self-made millionaire and author Steve Siebold. "Exposure to people who are more successful than you are has the potential to expand your thinking and catapult your income. The reality is, millionaires think differently from the middle class about money, and there's much to be gained by being in their presence."

Put your money to work

Need to stash your cash for the tax year? Here's what you need to know (Getty)

One of the most effective ways to earn more money is to invest it, and start as early as possible.

"The more you put in today, the much more you'll have later down the road because of the time value of money and the growth on investment returns," Michael Solari, a certified financial planner with Solari Financial Management, told Business Insider.

The simplest starting point is to invest in your employer's 401(k) plan. Next, consider contributing money toward a Roth IRA or traditional IRA, individual retirement accounts with different contribution limits and tax structures.

Another great option is to put any savings in a low-cost target date fund, a diversified retirement account that invests your money into a combination of stocks, bonds, and alternative assets. Though the market is impossible to predict, you're still going to get a better return on the money there than you would in a plain old savings account, with little to no work required.

Get a part-time job

If you want to earn more, a simple solution is to work more — and you'll get a lot more out of a second job than extra income.

You'll grow your skill set by working in a different field, put your brain to work in a different context, and expand your network. Plus, it's a great opportunity to monetise a specific interest of yours — such as photography, music, tutoring, or coaching — or turn your passion into a side hustle.

Check out high-paying jobs you can do on the side and read about how to start a side-hustle from a woman who earned up to $4,000 a month on the side.

Bury your head in books

Picture: (Getty Images/iStockphoto)

Rich people would rather be educated than entertained — if you want to be like them, cut the cable and dive into books on investing or personal finance, or pick up a successful person's biography.

"Walk into a wealthy person's home and one of the first things you'll see is an extensive library of books they've used to educate themselves on how to become more successful," Siebold writes.

Take billionaire Warren Buffett, for example, who estimates that 80% of his working day is dedicated to reading.

While the rich don't necessarily put much stock in furthering wealth through formal education — many of the most successful people have little formal education — they appreciate the power of learning far beyond the classroom.

Switch to a high-yield savings account

Yes, it's possible to have too much savings. If you have more than six months' worth of expenses stashed in a savings account or emergency fund, you should be investing the rest, at the very least in a high-interest savings account.

Though you're "never going to kill your financial future" by accumulating money, says financial planner Katie Brewer, "you're losing out on opportunity costs by having money sitting around ... especially if it's sitting in an account making barely anything in interest."

If you're risk-averse, one way to manage savings overflow is to move your money into a high-yield savings account, where you could be earning 1% interest, rather than the 0.01% earned in a traditional savings account.

Get used to doing uncomfortable things

If you want to build wealth, be successful, or get ahead in life, you're going to have to get used to uncertainty or discomfort.

Rich people, in particular, find comfort in uncertainty. "Physical, psychological, and emotional comfort is the primary goal of the middle class mindset," Siebold writes. "World class thinkers learn early on that becoming a millionaire isn't easy and the need for comfort can be devastating. They learn to be comfortable while operating in a state of ongoing uncertainty."

If you want to get rich, you have to be OK with being uncomfortable. If you're not, learn how to be, Siebold advises.

Start adopting this mind-set today with one of Siebold's suggested strategies: "Make a list of the five things you must do today that are uncomfortable but will help you build your financial fortune."

Set goals and visualise achieving them

If you want to make more money, you have to have a clear goal and then a specific plan for how to achieve that goal. Money won't just appear — you have to work at it.

Rich people choose to commit to attaining wealth. It takes focus, courage, knowledge, and a lot of effort, Eker writes in his book, and it's possible if you have precise goals and a clear vision.

Write down what Eker calls "play to win goals" for your annual income and net worth. Be realistic when setting a time frame to attain these goals, but at the same time, think big and don't be afraid to challenge yourself.

"The number one reason most people don't get what they want is that they don't know what they want. Rich people are totally clear that they want wealth," Eker writes.

Automatically save an hour a day of your income

According to David Bach, the bestselling author of "The Automatic Millionaire," the "most important" first step to take in building wealth is also the easiest: Automate your finances.

He teaches the "pay-yourself-first plan," which is automating your accounts so that a portion of your paycheck moves into your 401(k) plan or savings account before you even see it. It takes less than 10 minutes to set up automation, and calculating your income for an hour a day is simple, too.

Suppose you make $50,000 annually and you work a full-time job, 40 hours a week. You'll be paid for about 2,080 hours of work in a year, equaling roughly $25 per hour. Bank that much each day, and you'll "never have to worry about money again," according to Bach.

Establish passive income

What's better than earning income with little to no consistent work required?

Passive income, as it's called, is basically earning money while you sleep.

Though creating any streams of passive income requires an investment upfront, whether of your time or money, it can lead to huge payoffs later.

Common forms of passive income include real estate investments or silent partnerships in businesses, but it can also be generated by anything from making YouTube videos to using affiliate marketing on your blog.