Mary, these are all legitimate questions. Yes, there are no guarantees.
I believe it all starts with knowing what it is that you want. Where is your passion? If it’s science fiction, write your heart out. You’re right not to chase the trends if that’s not what lights your fire.
It takes sustained effort and commitment to build anything. What I would do if I were you is write something from the heart, and then share it with 10 of your friends. Everyone knows 250 people or so, right? If even one or two of those 10 people love what you’re doing, they’ll share it with the people they know.
Do that often enough and eventually you’ll build trust with people. That’s how all the greats got their start.
I can’t guarantee you’ll succeed overnight. But I can promise you that if you share with a trusted few, you’ll get some valuable feedback that will help you more than all the courses and life coaches in the world.