1) A voice (or series of voices) starts chattering in my head. Yes, I know this might make me sound crazy, but the truth is, when I start actually hearing my characters in my head, I know that this idea is the ONE I'm supposed to work on. For me projects always start with the voice of the narrator or main character so if I don't hear that voice, I know the story's not ready to be written.
2) I want to know how the story will turn out. This is why I write to begin with. I want to know the ending so I have to write the whole thing to see how the story turns out. If I don't care about the story or characters enough to want to know the ending, then I know it's not the ONE.
3) I get protective. When I first start a project--if it's something I really care about--I don't tell most people about it. Only when I'm at the stage where I need to get feedback do I open up and share the project with a few trusted readers. If I'm too open about the project at first, I know it's not something I'm really invested in--it's not the ONE.
4) I can't wait to write. This goes hand in hand with #2. When I know the story is the ONE, I can't wait to sit down and write it. At least that's true at first. After the "honeymoon" wears off, motivating myself to write can become more of a challenge but at first when I start the project, nothing can come between me and my writing.
5) I stick with it. Perhaps the best test of whether a story is the ONE for me is if I stick to it even when another, sparklier idea comes along. If I can shake off that new idea and stick to my guns on the first story, then I know it's the ONE.
What do you think? How do you know when an idea is the ONE?
Homework: Think about all the things you've worked on during DIY MFA and choose one that you'd like to pursue further. Don't worry, this doesn't mean you won't ever get to work on all those other ideas (they'll still be waiting for you when you finish with this first one) but it's important to have the experience of finishing an entire project. So, choose one idea and plan to see it through over the next however-many months you choose.