So a good working theory is something that you don't know whether it's right or wrong, but it is something you want to find out if it works. It might very well not work, but you want to know that too. It can be a UX pattern, a start-up financing model or an interactive video projection. If it is truly fresh and new and you are excited about trying it, you probably have a hunch how it might turn out, but you're not sure. It's a good start.
How do you find out whether it would work or not? You can do some research to see what colleagues, competitors and gurus are doing about similar ideas, so you don't repeat their mistakes and benefit from their experience. But then you should build your own.
You don't need to build the thing that you envisioned in its entirety with to understand whether it's good. You should identify the core of your idea, build that and see if it works. Formulate what qualify as "it works" too. But be flexible here. Many scientific break-throughs were the results of experiments gone awry.
Everything else is details. It is something like a Minimal Viable Product for start-ups. Identify it , build it, test it, measure it. If it works, carry on (you will have modifications to make though, it's okay and be prepared for them) if it doesn't, reformulate the idea or abandon it! There is absolutely no valour in persevering in doing something that is not working. Even if this is a process-based art piece and you are making a statement about usefulness and aesthetics as a socially-imposed criteria, it still needs to evolve to remain interesting.
If your idea doesn't work in the form of MVP, it doesn't mean it will never work, ever, for anybody. You can change the medium. You can change the format. You can change your target audience! Anything, really. Another funny thing about science is that so much of if is just tinkering. You know it's not working but you don't know which part exactly, so you modify one part at a time and try again and again and again until it does. It will. Perseverance always wins.
P.S. If you lack perseverance, don't worry it can be taught.