"How much plotting should I do for my novel?" you hear aspiring writers ask fairly continuously on the web and in coffee shop-cum-bookstores during readings. It's one of those questions that has an answer which depends on the writer, of course, but there are some things I've learned about my own writing process that might be of help to others who work similarly.
Plot, for me, is a blunt instrument that I try to avoid even thinking about except during the writing process itself. I stump along, letting my characters talk and do, and find the plot sorts itself out on its own. I tend to start with the kernel of an idea, but it tends to be vague. "There's a blackmail event and the characters have to get out of it" is about all I used on a recent project. By the time I was 12,000 words in the plot had developed into something that had several good threads and the characters were doing my work for me - they were in trouble and had to get out of it. Easy peasy.
That's not a testament to my plotting skills, I think it has more to do with having characters that are, in the writer's mind, real people. If they are, they'll do what makes sense for them, whether it's logical or not, and the story will progress smoothly.
Not having a detailed plot also allows you to write quickly, which is very important for me. When I write slowly I overanalyze, become stiff and find myself descending into a haze of fact-checking that impedes the ability to tell a story, and telling a story is your job as a writer. Not being stylish, or poetic, or grammatically creative or anything. You're here to tell a story. For me, going seat-of-the-pants lets me tell the story without hamstringing its pace and "feel".
Besides, when you finish you'll edit, plug plot holes, alter scenes and make any fumbles fantastic. That's what edits are for.
So crack open the laptop, choose a simple idea, build some real, memorable characters and see what they do. It can work very well.