I find that my strongest inspiration tends to come from the smallest places. My last three novel ideas have all started from a single, strong image with a feeling attached. Where these strong images come from has varied. One came from reading two very different books back to back and having them clash in my mind. Another came from a physical place I was in, imagining it 100 years in the future. The last one, I don’t even know where the image came from, it just kind of appeared.
I find that as long as there’s a strong emotion attached, that’s fuel that I can usually spin out into plot and character details.
Side note – for short stories, I have this same problem. It seems like everything I come up with wants to be a novel – which is such a shame because I really want to write short stories too!
I agree with Brad. Prompts are also helpful! And writing sprints. Sometimes, I’ll set a timer for 5-10 minutes and just type as much as I can (like a dialogue scene) even if I don’t know context yet or anything. Then I can glance back at what I wrote and flesh out an idea from there.
I’d love to hear from lots of people on this, but I find most of my inspiration from other things that I’m reading and listening to. Usually when I find myself without ideas, I’m not really consuming good stuff. I have to be filled to overflow!
For me, reading and listening are significantly more inspirational than watching. While I enjoy movies and TV, I find that they they don’t stimulate my mind in the same way.