The modern common way to become rich is to start a business.
Starting a business is the economical equivalent of a technological invention - you consider the cash flow of the world, find a shortcut for a better flow of money, and cash in on the difference.
A business starts by asking this simple question: "What can be done better?" If you can make a business system out of the answer and pay others to do the actual work, you're on the way to become rich.
Starting a business is a step by step process. Other stereotypical methods of getting rich (using force, winning the lottery, saving) are either too risky, too random, or too slow. Starting a business can favorably adjust these factors by introducing another one - brainpower.
In today's world, most people prefer the safety and stability of having a job. That means that work is relatively cheap, and it's better to be on the other side (offering jobs) rather than taking jobs.
Even though 90% of businesses fail, those are still great odds - start a business! Just make sure to use your brain.