For the high-concepts of stories? From my over-active imagination that is stimulated by life. The mundane morphing into the unusual, the ordinary that could shift to extraordinary with one tweak, the existential questions with practical answers, and the immediate concerns forgotten with a greater crisis; it's all fodder for a novel. An idea shortage is not a problem. An excess of ideas? Now there's a problem. Choosing which one(s) to pursue next? Choosing which ones to smash together into a new thing? Choosing which ones to abandon and which ones to beat into submission? Which ones get the investment of time and money? Which ones get pushed to the back of the queue? Which ones can be written in a timely manner and which ones will be long labors of love?
For the details of the story? Oh, now, this is the problematic part. The execution of the Great Concept. Again, abundance is the root of the trouble. Which path to trod? Which is unique without being alienating? There are drafts with whole tangents that seemed like a good idea that ended up not being compelling, that failed to develop the character, or that developed the character in such a way that the character is quite unlikeable. Sometimes, it's a lot of stabbing at shadows until one coalesces. "Would she really...?" is frequently uttered. Would my protag really react like that, go there, engage in that manner, solicit help, endanger that group, etc. How is my protag vulnerable without being weak? How is she competent and inclusive? How does she empower others to succeed? What is it she fears and how is that going to manifest? How does she deal with fear? How does she grow across the series without outgrowing the series?
Strangely enough, I can make a pretty swift command decision about which high-concept project I'll pursue. The details? Thems what makes writing a book a real challenge. Yet the magic happens when the brain is allowed to think, to truly muse and ponder.
And bourbon, bourbon helps too. 😈