1. Thinking short term
If you want to get rich, you have to start looking toward the future, not obsessing over your present situation. That means setting goals that might span years or decades, not just weeks or months. According to Smith, the longer you can stretch your thinking into the future, the richer you will become.
That's because long-term goals force you to grapple with big-picture questions such as, "How can I double my income this year?" instead of short-term issues, such as, "How am I going to pay my bills this month?"
2. Fearing change
Whether small or big, change can be intimidating. But giving up the fear of the unknown allows you to view change as an opportunity instead.
"The problem with the middle class is it assumes change will be negative most of the time," Smith writes. "Millionaires assume that all change, positive or negative, will benefit them."
Learning to welcome change, and welcome the growth that often accompanies it, builds confidence, which Smith says is key.
"Confidence is acquired through preparation and hard work," Smith writes. "Confidence is the result of working on yourself. It is the benefit of proving yourself to yourself. It is knowing you can handle whatever comes your way."
3. Craving instant gratification
Building wealth takes time, hard work and, most of all, patience.
Smith finds that millionaires are willing to put temporary comfort on hold to seek out long-term financial freedom.
"Middle-class people want instant gratification," Smith writes. "I was like that for many years. Whatever I wanted, I charged to my credit card or put a little bit down and made payments on the balance. Now I wait for the things I want because my goal is more freedom, not comfort.
"Rich and very rich people have developed the discipline of delayed gratification."
4. Thinking that you have do you everything yourself
Smith notices that while the rich get richer by setting up multiple streams of income, those in the middle class are apprehensive to do the same because they believe it won't get done right unless they personally take care of it.
"The belief that you must do everything yourself puts extreme limits on your financial potential," Smith writes. "Having a belief that no one can do it as well as you is ignorance. The world is full of talented people."
Stop stressing that something won't be done correctly if you don't have a hand in it and start putting more faith into the people who work for and under you. Delegate! That might even improve the outcome. As Smith writes, "Millionaires] believe they can find someone who can do it not only as well as they can, but even better!"
5. Believing that you can't afford to give
While middle class people often believe they can't afford to give, rich people see generosity as a necessity.
"Most millionaires believe in the law of sowing and reaping," Smith says. "They see money as a seed. Millionaires know that if they are generous, they will receive more in return."
Numerous millionaires and billionaires have become philanthropists. In 2010, Warren Buffett and Bill Gates teamed up to form The Giving Pledge, an effort that encourages the ultra-rich to donate the majority of their wealth to good causes. More than 150 billionaires have signed on, including Mark Zuckerberg, Richard Branson and Elon Musk.
"Not all millionaires are generous, but the happy ones are!" Smith writes.