I map out roughly. I put milestones down and think about characters. And then?
I plunge in. I'm a 30,000 word sprinter. I can manage 30,000 no problem, before I start to wander... and slow... and stop. I've got any number of 30,000 words novels that have fizzled and stopped. Add them all together and you have an epic longer than A Song of Fire and Ice (not that I'm obsessed or anything).
I'm jealous of writers (I'm looking at YOU Sophie Moss) who plan really well. It's not that I don't know how to plan - I've read all about snowflake methods and story fixes. And I've tried, really I've tried. I've tried excel sheets and folders, spider diagrams (mildly more successful) and Scrivener. I've sought advice, I've worked with critique partners.
I just don't enjoy it. Like dealing with my accounts, tidying the bedroom, doing the ironing and jogging it doesn't make it on my list of things I like doing. For now I'm going to take heart from my current hero, George RR Martin:
"There are some writers who are architects, and they plan everything, they blueprint everything, and they know before the drive the first nail into the first board what the house is going to look like and where all the closets are going to be, where the plumbing is going to run, and everything is figured out on the blueprints before they actually begin any work whatsoever. And then there are gardeners who dig a little hole and drop a seed in and water it with their blood and see what comes up, and sort of shape it. They sort of know what seed they've planted — whether it's an oak or an elm, or a horror story or a science fiction story, but they don't how big it's going to be, or what shape it's going to take. I am much more a gardener than an architect."
And then I'm going to try and work out where the hell I go to after the first 34,000 words.... maybe watering will help.