I'm a total pantser. The last time I wrote anything from an outline was when I was hired to write a screenplay for some guys in California. I can write from an outline when my motivation is a paycheck.
For myself though, nope. I might jot down a basic idea and basic characters but then I just think for however long it takes me to get to the point where I have to sit down and write.
I am very, very VERY particular about the flow of the story and the information that is contained in all aspects of said story. Maybe I've watched too many Ken Russell movies that lull you with quiet moments and then blast you out of your seats but for me those quiet times in a story between times of "action" are equally important and quite often convey more information than the "action" times. They're often the times that are most important and give the subliminal information that is needed to gel all of, or portions of, the story. (I once got chewed out by a director as a play I'd written had what he thought was a "throw-away" line in the first act. He dumped it and in rehearsal found out that the second act didn't work unless that one, ten word sentence, was in the first act.) This type of writing also makes me what they call, theatrically, a "tight" writer. It's Chekhov's gun... what can I say? My background is theatre/audio drama, that training never dies, it just morphs.
As I write I add or subtract characters to the story or ignore some until they pop up later. It depends on the length of what I'm writing. My current endeavor is ending up to be a multiple volume fantasy. I'm finding it surprisingly easy to keep track of everyone. But then I've put quite a few years into working this way so once I get myself into the frame of mind I need it flows and I follow.
As to setting, I have such a clear picture in my mind of how the story setting looks that I can tell you the colors of the flowers growing by the side of the road as the old rusty car rolls past them and also tell you what they smell like. This makes description hard for me to write because I can see what I'm writing so I forget to describe it.
For me being a pantser means
you know your characters. That doesn't mean you've written a bio about them including everything from their first kiss to breaking an arm. It means you know their "core" being. It still leaves plenty of room for expansion, but having that core is everything.
You know your setting, whether it's the attic of a haunted house or a raging river with rocks in it. You know it, you can feel it, you can smell it.
Even though you don't know your story yet, you know it. This way, no matter what situation you come up with, you'll know almost immediately if it's right or wrong.
Be prepared to make changes to the beginning as you flesh out your new creation and find your lead character really needs to be bald rather than have a full head of flowing russet locks.
Be true to yourself with your writing. Don't bend what you're doing to the latest trends or write what you think someone will like. Write what your characters want to say and do and follow their leads.
If you have no sense of adventure or discovery (or are afraid of stepping wrong), pantsing probably isn't a good fit for you.
Remember, there is no right or wrong way to write. The right way is the way that works for you. (But it is a good idea to try a couple different ways if you're not sure what works the best for you yet.)
Write hard, write true.
