Hi from Just Answer. What a great question. My take on the answer will personalize the pursuit, which you can customize for your strengths.
First, decide what your strengths are. Building an empire you control requires several character traits and the money to make it happen.
Most business tycoons I know were driven to succeed, and would have been successful in any endeavor. They saw their goal early on, and made decisions that targeted that dream.
One example is real estate. more people become wealthy in this country in real estate than any other industry. It requires some money and creditworthiness, but anyone can learn the part of the business they want to be in (own and rent homes, rehabilitate property, own commercial real estate, etc.). You have to make a personal investment in time and training to learn the business and begin to acquire your properties. The best training is to take employment with a leader in the aspect of real estate you want to know about, and learn what made that person successful. Copying what successful people do is the easiest way to learn what to do to be successful.
Some people like to be investors, to build their wealth that way. It's not my favorite, since so much of the growth of those investments is outside of your control. An investment in Microsoft thirty years ago would have made you a fortune, but picking just that would have been very lucky. You must have other skills, like personal drive and likely a good financial education to understand the investments and make good choices.
Some prefer to get professional level education, to invest in themselves. While there are still self-made tycoons, especially in real estate, it will be hard to participate in wealth building without education. Doctors, attorneys, financial businesspeople, all invested in an education. Consider investing in the best education you can.
Study the lives of notable tycoons. Warren Buffett in investments. Bill Gates, Steve Jobs, Jeff Bezos in technology empires. Donald Trump (he inherited much of his wealth, but learning about the rise and fall of real estate values and how to survive is mandatory for real estate pros. These people did not just grow their own wealth, but learned the value of investments by others. Warren Buffett, for example, assembled investors and retained an ownership stake with no money of his own.
Lastly, I would learn the people skills you will need. Most wealth building requires learning how to treat people, and how to retain your focus on your goals. The rest is a mix of determination and learned skills, and a choice of businesses to enter.
You might consider reading the Wikipedia life synopsis of George Steinbrenner, who was known for his ownership of the NY Yankees baseball team. He built his wealth through purchase of his family's shipbuilding business (with other investors) and parlayed that into real American tycoon status. http://en.wikipedia.org/wiki/George_Steinbrenner is the link. https://en.wikipedia.org/wiki/Mikhail_Prokhorov is the link to a Russian tycoon story, New Jersey nets owner Mikhail Prokhorov. His story is notable in that he made the correct decision each time with his wealth. I also like the Mark Cuban story. His wealth building came in technology, but his story is notable because he did not fall in love with his assets, and sold when the price was right.
Thanks for asking your question at Just Answer. I hope this unconventional answer makes sense, and guides toward your own empire building. I'm PDtax.