I’ve always been inclined to be a pantser. Both in life, and in writing. I shan’t elaborate further on how this disposition relates to the former. But the latter probably comes from Stephen King, whose 2000 how-to/autobiography On Writing: A Memoir of the Craft is a book I would highly recommend for anyone looking to take up this art for themselves. Chock full of useful tips and tricks on writing fiction, from an undisputed expert on the subject.
Somewhere in the aforementioned tome, King states that he always starts a book having no idea how it’s going to end. Decisions on such matters are to be left up to the characters, who take on a life of their own as the author writes, driving the story in ways the author never anticipated.
That approach (or at least some badly misinterpreted variant thereof) is one I’ve incorporated many a time. There would be a general idea about plot devices and where the story would end up eventually, but for the most part I would take an improvisational route to writing fiction. The results were hit and miss. Making it all up as you go along is all fun and games until you end up writing yourself into a hole. But never a waste of time. There are certain genres where one must learn to play before learning to hunt…
The Environment is a character in this crazy yarn I’m currently tinkering around with. Like it tends to be in many a work of speculative fiction. All other characters and events spring from the Environment, so the Übercharacter required more fleshing out than any other character. I had to invest the time to wrestle with the Übercharacter, like a bear cub wrestling its littermate. So It could hone Itself, eventually becoming strong enough to take off.