I’d say your question is too generic, but here’s some general advice.
* Your choice of initial project probably doesn’t matter. Whatever you start with will probably fail, and whatever eventually succeeds will probably be after many iterations of learning from failure. You’ll take better photographs if you take 100 pictures a day, instead of trying to figure out the perfect thing to take 1 picture of before you start.
* Get experience executing on an idea from start to finish, so that when the right opportunity shows up you can just go, instead of having to learn a bunch of tangential stuff like accounting, insurance, or legal stuff. You’re also more likely to find some problem worth solving, by identifying people’s pain points, if you’re out there doing instead of thinking about it.
* You’re talking about starting a business, not working as an employee, which is a completely different mindset. As a business owner, you don’t get anything for just showing up. It costs you something just to show up and have the lights on.
* As a business owner, it’s all up to you, no one is coming to help you, and you have to embrace that. You have to find a way to be fulfilled by the process. There is no low hanging fruit. You’re going to have to go hunt it down and kill it yourself.
* As a business owner, you’re trying to do something, and it will either work or it won’t. The plane will either fly or it won’t, and you’re not going to figure out how to invent a plane by asking other people for ideas. You have to figure it out. Figuring it out is the valuable part.
* You (probably) need to be obsessed. If you’re not ignoring your friends on Saturday night because you’re sitting at home starring at computer screens of code, because that’s actually what you’d rather be doing, you probably won’t make it. I’ve never seen anyone make it solely based on the desire to quit their job.
* You need to have some reason to keep going. Quitting your job probably isn’t it. At some point it will get very hard, and you’ll ask yourself why the hell you’re putting yourself through all of this misery. At that point, if you don’t have a compelling answer to that question, you will quit.