You start with a good set of assumptions. After all, you know your audience. You do your research to challenge some of those assumptions. You test the idea by getting a small version out there (Eric Ries’ MVP concept from The Lean Startup). Is there some evidence that it is actually viable?
The key is to choose which ideas to turn into projects. If you get some evidence, then it starts to be about the execution. Any worthwhile project probably includes at least one large idea. But it will probably require a bunch of smaller supporting ideas, too. Do you start to see those ideas crystallize?
Then ask yourself—do you have the persistence to stick with an idea? Do you love this idea enough to make it a project? Is your idea strong enough to withstand that persistence? It’s going to take a lot of time and effort, so it’s good to know whether you (and your idea) are up for it.
As you iterate, when does the project become a product? When does the product become a business?
You won’t know any of this unless you get your ideas out there and start to interact with the people you are trying to serve. This is why NDAs are stupid. How is your idea going to grow if you don’t get it out there? Obscurity is the enemy of creatives, not “stolen” ideas. If it’s all about the execution, the protection instinct isn’t going to help you. It’s actually going to slow you down. You won’t learn fast enough if you’re not interacting with your audience.
If you’ve built up the trust of an audience, then people are going to look to you to solve this particular issue. This is why content marketing is so important. They want to buy from those they trust. Be the one they trust, then!