One thing that's a pain about writing a splurge first draft instead of planning, is that you get to know your characters as you go along. You also develop and change the characters - I know my lead character was fairly unlikeable when I first wrote her. She became more interesting and warm as I wrote the middle chapters. My second chararcter grew from a whiny brat into a grown up during the process, which probably does reflect the experiences she had, so that was helpful. But my bad guy, he started out as a he and became a she, gained about four hundred years and lost a hundred pounds. Not to mention her personality becoming more charming psychopath and less ravening monster. So I'm writing character sketches. One technique that I have found useful in short stories is to interview my characters about related (or unrelated) things. I once had a long conversation with a murdering nut case about conservation but it did reveal why women trusted him. I realise to some people that makes me crazy, talking to my imaginary friends, but it did make him easier to write! Presently I'm working on the smaller characters, making them more well rounded. One of the criticisms I had about a previous novel was that the minor characters were more fun than the main ones, and I realise I'm in danger of doing the same.
I've been recommended a book, The Marshall Plan for Novel Writing by Evan Marshall, and I'm at least trying to work from the early chapters. I don't think I'll ever write each scene in meticulous detail, but it starts with choosing a genre, coming up with a story idea (and being able to put it into words) and developing your characters. That's what we're trying to do in the preparation for our dissertations, so it makes sense to be able to say this is what my novel is about. One of our tutors recommends we put that on a post-it and stick it to the computer screen. So it's pen and paper, character sketches this morning, then looking forward to interweaving story lines. Excellent. Almost sounds like I know what I'm doing.