I suppose you could say my second writing career dates to about 1998. I took stock of myself and found (a) one unfinished novel (I was 12 months in to it), (b) one finished, unsold novel with structural problems (bits of it have since re-surfaced in the form of "The Atrocity Archives"), (c) one short story sale in 1998 -- and that was a reprint of something I wrote in 1991. I was in my early thirties and I realised that either I should give up, or I should get serious about writing. I started by setting myself a goal of writing *and selling* four stories a year, and a second goal of getting into the magazines that get name recognition -- Asimov's, Analog, F&SF. Somewhere in the preceeding decade I'd cross-fertilized a chunk of ideas between the biological and computer science, and I'd also learned a little bit more about human nature -- enough to handle characterisation better than during my late teens or early twenties. (Parenthetically: this is one of the reasons why we often see new authors erupt on the scene aged thirty-something -- they've finally learned enough about human nature to have something interesting to say about it.) So in 1998 and early 1999 I finished and sold "Antibodies" and "A Colder War" (which got me into the Year's Best SF anthologies), wrote "Lobsters" (which got me into Asimov's and onto the Hugo and Nebula ballots), completed the novel now know as "Singularity Sky", and got serious.Link
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.