Back in the 1990s, the high-tech people got it down to a system. It was actually the same system preppie / Ivy Leaguers had been using for years, but in the 1990s entire books were written that explained how it worked.
First you need to save up as much money as you can. I mean actual money in the bank, not credit cards or loans. When I went through this in the 1980s, we had $5,000. The next step is to borrow the same amount on credit cards, then borrow the same amount again from friends and family. (That last one is called "the friends and family round of financing.") Then, when you run out of money because everything is taking longer than expected, you go back to your friends and family and borrow some more. That's how we got $15,000 plus another $25,000 when we came back for more.
The next step is getting money from angel investors. Ideally, they should not be total strangers. In our case the angel investor was a high-powered accountant who was introduced to us by one of our friends-and-family investors. He got four of his clients to each invest $25,000.
The next step after that would be venture capitalists, who usually have only one goal in mind: to take your company public, which means the stock would become available on the stock market through a process called an IPO (initial public offering).