Not so fast
I wrote my first two books on the fly. From one page to the next, I did not know what was going to happen with the story. I loathed planning. Why did I write them like this? Well, when I was a teenager, I read a piece by Stephen King about his method of writing, and that was how he did it. I thought, oh, right, so that's how writers do it.
This improvisational method certainly suited my first book - I was fairly gripped by the story throughout, and this quality has been commented on by reviewers, so I guess it worked. But that book was written while I was working as a teaching fellow full time. In a steady trickle of 500 words a night, in other words. Now that I'm writing full time, it's difficult to produce less than 1000 words a day. When the thing you're writing is plot-heavy (as the new Saskia Brandt novel is a thriller, then this certainly qualifies), this stretches the improvisation somewhat. I also recall that, when the novel passed through the hands of my capable editor (Aliya Whiteley, a writer in her own write), she suggested some basic changes to its structure that, at the back of my mind, I already knew needed to be done but I couldn't, simply, be arsed because of the amount of work it required. Once you've written 100,000 words, changing its direction is about as straightforward as shifting an asteroid on a collision course for Earth. This kind of change, however, might have been visible had I worked over the story before I wrote it.
Then yesterday I came across this blog entry from Eric von Rothkirch, and it makes a good deal of sense. I still think that drafting holds the upper hand in the coolness stakes (and is particularly suited to more character-based pieces, like my last novel, Proper Job) but when it comes to a plot-heavy work, there's enough evidence to convince me that a change in writing habits is worth a shot. (I'm not a big one for 'if it ain't broke, doesn't fix it' anyway; if I had that attitude, I wouldn't be able to improve as a writer.)
So that's what I'm going to do. I'll plan the story beforehand. This, I think, is a much less enjoyable way of working - or, rather, it was the last time I tried it - but it should produce a better mash of theme and plot. We'll see how it goes. At the end of the day, it's well and good to maximise the fun you have while writing, but it's the product that's got to be the best it can be.