If you do everything you can, and you're still stubbornly stuck without a good idea, the best thing to do is stop.
And go do something else.
Or go pamper: Take ridiculously good care of yourself.
Go move. Take a walk, a run, a hike. Dance.
However you do it, it's time to give your project (and yourself) some space.
Take a micro break. Both James Scott Bell and Julia Cameron talk about writing down a question you have at night, and then getting up and writing about it first thing in the morning.
Wonderful things can happen in your brain overnight. And in the morning, you write 'em all down!
Mmmm. I love that kind of near-effortless idea making!
Or, take a macro break. Like this:
Once, at the end of summer, I quit writing. I was done.
Out of ideas for workable novels, out of ideas for the drafts that were waiting for me, out of ideas for how to fix anything, including myself.
So for three months, I just read novels. (And felt a bit depressed, but we can skip that part.)
I read and read and read, and I didn't even try to think about new ideas.
And then one October night, I got an idea literally out of a clear black sky.
I was staring at the stars when the crux of a novel dropped right into my head. It fueled a beautiful, dreamy project (which I plan to come back to one day!).
Better than the new project was that feeling: of being unstuck.
Of being hopeful again. With another trail of ideas showing that the writing life was still mine.
So sometimes? Sometimes you really do just need a break.
Give yourself some grace. Do something good for yourself.
And that idea you've been desperate for? Might show up when you least expect it.