How do you build good software that users pay for?

This is somesort of a vague question but, I am in a third world country and I see posts on techcruch on how startups make lots of money is silicon valley. The funding literally competes with my countries national budget. I want to build such software that gets funded. I am sort of a solo dev with full stack skills. I want to start and buy into the software as a service deal so to say but I am lost and literally broke.