13 strategies to save a fortune, from real people who retired before 40

Flickr / Daniela

Contrary to popular belief, you don't have to win the lottery, inherit a windfall, or even earn a Wall Street salary to retire early.

Consider "Mr. Money Mustache," who averaged a $67,000 annual salary working as an engineer for 10 years before announcing his retirement at age 30. Or Jeremy Jacobson and Winnie Tseng, whose combined annual salary of $135,000 was enough to retire in their 30s with a multi-million dollar net worth.

To help you get started on the road to early retirement, we rounded up tips and strategies from regular people who retired before age 40.

Read on to see how they did it:

Think about money as something to invest.

Peter Adeney, better known as "Mr. Money Mustache" turned quite a few heads when he announced his retirement at age 30 back in 2005 by saving two-thirds of his and his wife's take-home pay.

The 30-something retiree's secret boils down to the habit of thinking about money as something to invest rather than something to spend.

"The growing part of my money is pretty simple," he told Farnoosh Torabi on episode 38 of her podcast, "So Money." "I just like the idea of keeping all money invested. So if I run into a surplus sometime, I don't think of something to buy with it, I think, 'OK, I better get rid of this money and put it to work again.' So, I sweep it out of the bank account and into regular index funds."

While a raise, generous birthday gift, or lucky lottery winnings may trigger a shopping spree for most of us, Mr. Money Mustache's instinct is to invest surplus money, which helps eliminate any spending temptation that may arise. 

Maximize your income.

"Becoming financially independent requires building up a large amount of capital, a task made much easier by earning a high income," explain Jacobson and Tseng of Go Curry Cracker!, who committed to saving 70% of their income for about 10 years in order to retire comfortably in their 30s.

While a six-figure income certainly helps, it's not essential for early retirees, they note: "For those with no interest in attending college, or those with a degree in a lower income field, time outside of work can be spent on a side hustle ... No matter which path you choose, with hard work and dedication it is possible to grow income over time. By inflating savings rather than lifestyle, this will result in rapid growth in wealth."

Read about 50 ways to bring in additional income, high-paying jobs you can do on the side, ways to earn passive income, and how to start a side-hustle from a woman who earned up to $4,000 a month on the side.

Invest the difference.

Once you've maximized your income, you'll want to put as much of that money to work as you possibly can. One of the most effective ways to earn more money over time is to invest it, and the earlier you start, the better. 

"Learning to invest is probably the most valuable skill one could ever learn," write Jacobson and Tseng. "The stock market is one of the greatest wealth creating vehicles ever created (perhaps second only to a bicycle) and is a critical component of building a portfolio that will support a retirement of 60-plus years."

For more information on investing, read up on the basics before diving in.