A common downfall for "pantsers" is realizing they've written themselves into a corner, and I used to be one of those. No longer!
Pantser: A writer that writes 'by the seat of their pants' with little to no planning ahead. Also known as pure inspiration writers.
I used to be the biggest pantser on the face of the planet. I didn't have a plan. I just launched right into writing and let the story take me where ever it led. I wrote a few books this way, but they haven't seen the light of day because even I find them to be aimless rambles. I'm amazed I finished them at all because I would often find myself either contradicting myself to the point of needing to backtrack and heavily edit everything to make it match up... or I would find myself unable to continue because I had painted myself into a corner, so to speak.
I hear many writers ask, "But how else would you write?"
Let me let you in on an open industry secret.
Barely anyone "pants" it. They may think they are, but the reality is they are a "plantser" and not a real pantser.
Plantser: A hybrid, whether they realize it or not, of a pantser and a planner. While they go where inspiration leads them, they still have at least some idea who their characters are and how, in general, the plot will go.
Planner: A writer who plans their plot, characters, and everything else into a neat general outline (or in greater detail) before actually writing the book. This writer is one part architect and engineer but of story.
When I wrote After Oil (now called Ashes in Winter), I was a plantser. I knew my characters inside and out and I had a general idea of what would happen but I wasn't quite sure on how my characters would react to it. I had to be flexible enough to accept that, to remain in character, they could choose a different option than the one I had laid out... and roll with it when it did change or keep going if it didn't.
However, I have now grown into creating detailed character descriptions including rolling skills and statistics using a pen & paper RPG that suits the story at hand, plus detailed maps, locales, and other set fixtures. The plot comes after, but goes through the same testing and planning.
I will make sure that my plan will work before I start writing by imagining, in short and point form, how the characters will move through the story. If in this stage I figure out the characters wouldn't go that way, I nix the scene. I also identify pinch points and how each scene adds to the story logically, as well as when the scene is happening so we don't jump back and forth.
This is especially true in the later books in the series as things became more complex.
I also find that writing comes far, far easier now than "waiting for inspiration" to strike. All I have to do is write the story as per the outline. First drafts that are far more solid than my previous first drafts fly out of my mind and through my fingers as I type. Revisions and rewrites are far less painful.
Instead of tugging and pulling at threads to make sure I haven't missed anything, I know I have a solid plot and story. I can concentrate on making sure I am showing instead of telling, and then move from that to giving it style and flow.
There are numerous books on the subject of how to outline a book.
The staff at Pen Knights Press (my publisher) tossed me The Snowflake Method and it's now something I swear by, but you may find something else that works for you.
And that's the key thing.
It doesn't matter if you're a pantser, a plantser, or even a planner... whatever works for you is what works for you.