I am not a pantser. That way (for me) lies idiotic plotlines and tangents that have nothing to do with anything and writers block when I can’t figure out where to go after my ridiculous idea strands me.
I start with a vague idea, a plot bunny that attacks me in the shower or while driving. The idea marinates for a while, and different possibilities for plot and characters pop into my head. Then I start creating a rough outline, but I don’t start writing until I know how the book is going to end. Sometimes I write the last scene before I write the beginning of the book — it’s good to know where you’re going.
Sometimes I create a full-on, very detailed outline for the entire novel. Sometimes I use a looser, bare bones outline with just major plot points.
I always spend some time getting to know my characters. I usually complete character questionnaires, find photos of random strangers online who have a resemblance to the character in my head…complete dossiers of physicial descriptions, SAT scores, speech tics, etc.
By the time I sit down to write, my characters are fleshed out, the story is fleshed out, and all I have to do is write it. Simples things up quite a bit and prevents writers block.