Image: 401k 2013.

While most of us born in America are already richer than we think -- consider that if you make $35,000 annually you're in the top 1% of the world according to many estimates -- many of us realize that becoming a millionaire is attainable for the average American. It all comes down to managing your wealth intelligently, taking calculated risks, and paying attention to the small details over a long horizon. Here are some tips to help you on your journey to becoming a millionaire.

Brian Feroldi: One surefire way to become a millionaire is to consistently spend less then you earn and invest the difference. That's an easy-enough concept to grasp, but putting it into action can be a difficult challenge. That's why I'm a big fan of focusing on at least one of the "big three" spending categories -- housing, transportation, food -- and find a way to optimize it in order to save a huge amount of money.

The transportation category is an especially ripe area to attack. The average American family spends 19% of its total income on transportation-related costs each year, which ranks second only to housing. Thankfully, there are many different ways to drastically reduce your spending on transportation, and if you can do so, your journey to a seven-figure net worth will be much easier.

One easy way to save on transportation expenses is to buy only used cars. Doing so will allow you to sidestep the enormous depreciation expense that cars endure during their first few years on the road, which will easily shave thousands of dollars off of your transportation costs each year.

This is my personal favorite way to save, as my last car purchase was a three-year-old Toyota (NYSE:TM) Prius V. The model I choose was in terrific shape, and came with all the features that I wanted; yet I was able to have the original owner eat nearly $10,000 in depreciation cost by simply buying used. 

If you're willing to go this route, it's important to focus on buying cars with a clean history and a good reputation for reliability -- which the Toyota Prius certainly has. You might also want to spend a few bucks getting it checked out by an independent mechanic for any major flaws. Doing so will give you a great chance of buying a reliable car that meets your needs, and will make it easy to devote a greater portion of your paycheck to investments 

Jason Hall: Most people attain wealth through their work, and the best way to grow your work wealth is to make yourself more valuable to employers. You won't become a millionaire overnight with this method, but the reality is, most millionaires took many years to build their wealth. Even Warren Buffett built up the vast majority of his wealth after he turned 50.

If you really want to get to $1 million or more in net worth, plan on taking a long time to do it, and start by investing in yourself and your job skills. A good place to start is to go back to school for additional certifications and training that will make you more marketable, and add to your value in your current field of work. If you're stuck in a dead-end job, or have limited growth potential in your current field, be ready to take a step back in the short term if you really want to achieve financial success in the long term, and start training for a new career with better long-term opportunities for growth. 

It might take a lot less than you think. If you can come up with an extra $15,000 per year that you can invest, you could turn that money into nearly $1 million in just more than 20 years, based on the S&P 500 average annualized rate of return of roughly 10% during the past few decades. 

Selena Maranjian: One trait common to many millionaires is valuing every single dollar. Many people using coupons at supermarkets, or waiting until Wednesday to fill up their gas tanks in order to get $0.05 off per gallon of gas, are millionaires. Little sums saved can add up to a lot over time.

One way to save without even feeling a pinch is to use a credit card that rewards you with cash back. A great example is American Express's (NYSE:AXP) Blue Cash Preferred card. It charges a $75 annual fee, but then rewards you with 6% back on supermarket spending, 3% back at gas stations, and 1% back on other purchases. If you spend $100 per week on groceries, that's $5,200 per year, and it can net you $312 back per year. Spend $50 per week on gas? That's $156 in cash back. (The Blue Cash Everyday card charges no annual fee and offers lower cash-back rates of 3%, 2%, and 1%.)

Spend a little time thinking about your spending habits, and you'll likely notice some places where you can cut back easily and profitably. Do you add a $1 bottle of water to your lunch order routinely? That could be costing you $250 per year. Could you brown bag your lunches twice a week, saving, say, $15 per week? If so, you're looking at close to $800 that could be plowed into your investment accounts. Little sums add up.

Daniel Miller: My colleagues all posted great ideas and tips, so I'll just use a personal example: Don't be lazy! There are people who live to work, and there are people who work to live. If you want to be a millionaire, you have to accept you're likely going to be the former of that previous sentence.

A personal example of mine: I had just graduated from college in 2010, and was fortunate enough to find a marketing job at a medium-sized company right away. However, because of the products we designed, marketed, and sold, it was difficult for me to really expand my knowledge from personal use of the products in my spare time. For instance, say your company builds large cranes; it's a little difficult to get personal use and come up with new ideas in your spare time -- unless you happen to have a crane capable of building a skyscraper in your backyard. 

As an ambitious young man, I wanted to spend my extra time expanding my knowledge base, creating additional income, and investing it to grow my wealth more quickly. I decided to read and learn about the stock market, and about three years later, while still working my regular salaried marketing gig, I had an opportunity to write part-time for The Motley Fool. I was able to stash away that extra income working a couple of extra hours per day, and then invest it. It created a virtuous cycle for my market knowledge, extra income, and investing opportunities. 

If you want to become a millionaire, the best tip I can give you is to work harder. Find a second job that you enjoy and can further your knowledge in a desirable area. It's 2016, and more opportunities across the globe are accessible from your desktop. You just have to find a way to make it happen!

Brian Feroldi has no position in any stocks mentioned. Daniel Miller has no position in any stocks mentioned. Jason Hall owns shares of American Express. Selena Maranjian owns shares of American Express. The Motley Fool recommends American Express. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.