Oh, good to see I'm not the only chaotic, scatter-brained eccentric!
For me, personally, everything starts with a random thought.
Like, one time I was in the middle of writing a scene between two characters where the Lady was a professional author herself and the Man was her sort older-brother/best friend/BUTACTUALLYHE'STOTALLYCRAZYFORHERANDALSOKINDOFHATESHER (.....Let's not get into that long story...AHEM!).
Anyway, Lady was trying to get help figuring out where to go in her story and I was sitting there, screaming in pain trying to figure out WHAT the story she was writing was supposed to be about.
Then 3 minutes later I had a title, "Secret Angel", and BAM!
I've got like the first 75% of this story for a character in one of my stories FIGURED OUT! And...well, honestly that's kind of how I write.
My brain just comes up with a character name or a question that my brain then finds weird ways to answer.
Sometimes I'll see a picture (an actual photograph, a drawn image, or digital artwork) and I've suddenly got the first chapter already chilling out in my head, waiting for me to write it down my next free second.
Heck, one time I was in the middle of work and a few sentences pops in my head and I had an entire book swimming around in my brain, shouting for me to start typing once I went to my lunch break.
This is the scene, btw, along with an extra tag-on from further in the story, after one of the main characters grows up:
Pools of red blood, gathering and dripping from the ceremonial altar.
The high wail of a woman's voice in pain and horror as the news was announced.
The low rumble of a man's voice as he increased his volume to be heard over the woman.
The wet sound of flesh being pierced by metal.
...These were what filled and assaulted my senses as I raised my head to stare at the sight.
…Yet, it was beautiful in the horror of it all.
* * *
It was the first major event that happened in my life.
As with the countless females in my bloodline, our mother's were killed the moment we were born.
I was merely the newest in the long line of corpses-to-be.
In general, I start with something random and go from there. Sometimes I have some part of the story figured out and I try to get it to work in the way I want. Most of the time, though, I literally find out what's going on sentence by sentence. Suprise characters are a constant in my life. sigh but I love them anyway.
One of my favorite characters in all my works, Bren (the above-mentioned Man), came from a random scene that I had no idea what was going on.
Like my characters were having a nice little family bonding moment at the beach and then everyone's freaking out because Sera (the above mentioned Lady) has gone missing while swimming in the ocean.
Then, while I'm internally freaking out with everyone else, biting my names and demanding to know where the heck Sera is at, this sulky preteen is what I get instead!
Anyway, I figured the scene where he first shows up was a one-and-done scenario, but he kept finding ways to sneak his little self in until I literally had an entire arc focused on this one kid for like....8 or so chapters? Now the man demands his own book, wagging his finger with sass taunting me with his 'You know you wanna...! '
...Dang it if the man ain't right, too!