I've been asked many a time, 'where do you get your ideas'?
The truth is, they just leap upon me. As a writer, writing is in the forefront of my mind so if there is a snippet of inspiration, a vision of a person or a setting, I think about it in terms of if it would work as a story.
Non-writers probably get this too but they ignore it because they have no desire to write.
These half-formed ideas then grow the more I think about them. I then start writing down whatever comes to me. It could be a snippet of conversation, the vision of a character, a specific detail of a new world. Eventually these grow and grow until I have something tangible to work with.
Then I'll write down some more ideas, think about the whole thing in more detail and try and form a proper plot from it all. If that' a struggle then I leave the idea alone to fizz and grow a bit more.
A lot of my story ideas come from a dream, Sanctuary certainly did.
So, do you have a particular process your ideas go through before they turn into full plots?