For as long as I can remember, I've thought about writing a book.

The time has come in my life that I have to stop 'wanting to' and actually 'do'. The ability to self publish through Kindle and other eBook vendors has now made this easier than ever.

My issue now, however, is coming up with a suitable idea / synopsis for my story. I don't want to make money out of this, just complete a goal I've had forever.

Does anyone have any tips about how to formulate an idea for a story?

When you have this idea in place, do you (writers) just 'go with the flow' and write, without too much planning, and see where the story takes you? Or do you find storyboarding is the only way to go?

How to formulate ideas is going to be a different answer for everyone. It's art.

I don't storyboard, but I do have a solid idea of where I am going and/or "the message" I am trying to convey. However, the outcome does change while I am writing and I am often surprised by it. I've written both with direction and without it. It just depends on how solid my idea is at the time.

Also, I never throw anything away. If I am not using it now I might have a use for some of it later. I often hear, "Throw out your first draft." I've never done that; opting instead to refine, refine and refine some more. It works better for me. I have found that going back to something I've "thrown away" can be used at some point when looking at it in a new light.