Don't wait for the muse. She has a lousy work ethic. Writers just write.
I learned to produce whether I wanted to or not. It would be easy to say oh, I have writer's block, oh, I have to wait for my muse. I don't. Chain that muse to your desk and get the job done.
That's how it is: some people are content to wait till you ask, while others jump right in with the whole story.
You always need that spark of imagination. Sometimes I'm midway through a book before it happens. However, I don't wait for the muse to descend, I sit down every day and I work when I'm not delivering lambs on the farm.