Ideas come and go. I think of at least three to four ideas a day for books. I have a notebook full of potential projects.
Sometimes I pick up my notebook, turn its pages, and scan my scribblings until one of these ideas gets my attention, and I spend some time with it. It might become a blog post, a short story, an outline, ... Who knows?
Other times, I already know what I want to work on, but I don't know that I know... until one day, the words just pour out of me, and the first draft is done.
Then comes the editing, the moment of truth. At times I keep what I've written and just try to improve my writing, but not always. Sometimes, the editing process takes me to an unexpected place, to that place I already knew I wanted to visit but didn't know I knew.
Writing is magic.