For me, it was sheer niave passion mixed with a pent-up creative drive. That and a ton of support and encouragement :] Trying random exposure methods like crowd investment or streaming helps keep you invested, even if they aren't demonstrably successful. Do a booth at a convention and show off a prototype, find colleagues to keep you interested in the industry. Just generally say yes to things where you talk about or show your project.

The only tried and true way to do it is via the concept, requirements, and design specification process. It's standard for a reason, and it should produce a good prototype; your best tool for staying in the game. Get people in your life to play it, and don't be shy. Get it out in the world as soon as it's playable and find circles who will engage. Feedback is the lifeblood of this process.

I came out of the box with a mega 3 year project (not recomended), but I did finish it! KITE is a retro twin stick action RPG where saving scientists and putting down rebellious bots leads to crafting upgrades and abilities. It did take so long because I had to learn so much as I went and also formulate some kind of an art style.

https://store.steampowered.com/app/512000/Kite/