To state the obvious, as I believe I am rather good at doing, the beginning of any piece of writing is the first draft. Sometimes, it’s also the end, either due to unwillingness to redraft, or just because the writer doesn’t consider it salvageable.
There are different ways of going about creating a first draft. Some people like to plan it all out, make an outline to follow, whereas others just go for it, maybe with a rough plan in their head, but nothing on paper, and write it all straight out.
I’ve traditionally been part of the latter group. Sometimes I’ve just made it all up as I go along, while sometimes I’ve had a start and an end point in mind, and maybe a couple of other things I want to happen at some point. I’ve held the view that it’s easier to write when there’s not a set of stepping stones to work by, and that the extra effort that will almost inevitably be required to revise a first draft written this way is worth it for getting it out.