How do you start a story? Is a question that gets asked a lot. Some writers like to outline before they start writing. Other writers like to do an outline and character sketch before they start their story. Me. I like to just start writing. I sit down in front of the blank screen and start typing whatever comes into my head. Some times the writing is good and most of the time its not. But as I write I don't worry about wether its good or bad, I just listen to the voice in my head and write. Later it will be time to rewrite and outline and do a character sketch.
Some days I could write for hours just listening to that voice in my head. Then other days after a few minutes or so my imaginary friend stops talking to me. I sit and stare at the few words or few sentences that our on the screen and wonder now what. I know there is more to the story. The next day I'll come back to it and my imaginary friend will start to talk again.
Most of the time free writing gives me the bases for a good story. During free writing the character reveals themselves. Later I will do a sketch and ask my imaginary friend questions about themselves.
Later I'll read over what I have written and say what if this happens to my character. How will they react? What will they do? What is this characters goals? So I start to develop conflict. Putting my character into a bad situation. Giving that character something to fight for. Something that will change the character hopefully for the good.
Once I figure out if this story idea is good enough to develope into a story then I'll do an outline. It is usally a rough outline that changes a lot as I write the story, but the outline gives me a road map to follow. Then when I get stuck in the middle of the story (which I always do) I'll go back and outline again. Asking what if this happens. How will the character get out of it?
Usually, when I get stuck in the middle of the story, I need to go back to the beginning and see where it all started. Or figure out the end and map out how my character will get to that end.
I don't know if most readers realize how much time goes into a story. A writer does not just sit down at the computer and write and it comes out perfect. It takes several rewrites to make it just right.
Even when I'm not sitting down at the computer, I'm still writing. I observe what is happening around me and how I can use it in a story. Or a scene that I've been writng will play out in my head and I think yeah, that will work for that scene so I rush to jot it down before it leaves my head. Or I'll just think about characters and let them develop in my head before I even start writing their stories.
So as a writer, I'm always writing. There is always a story developing in my head.