Not sure I'm qualified to answer this question, since I just started posting my series this last week. But for me, personally, I don't really worry about plot, not while I'm writing. The thing is, right now I have two series, should be three, but for the two series, I've been planning them for about two months now. That's not long for me. Another series I'll be working on I've been working on for at least six years. Planning for me consists of all the usual stuff. Characters, back stories, themes, development, settings and world, languages, cultures, geography, systems, services, politics, social structure and classes and so on. The majority of characters I've written always have multiple versions, different iterations, numerous backstories because I work on them over time, and as I accumulate these different forms, I take all the pieces and combine them to form a rich, complex character. The natural clash between different versions ends up becoming a character's innate contradictions or personal struggles. Of course, I try to think about plot, thinking of future events and the flow of story but it really doesn't work for me. My characters will say and do things I couldn't have anticipated, typically because when I'm plotting, I don't have their full mentality in mind. Plotting tends to be a plan of the big picture, so I'm looking at the world, the relationships, the ideas, not the character and their surroundings, the instincts to run or stay, the desires and opportunities they see directly and indirectly, and really, those decisions they have are the plot. But this doesn't stop me from planning. To be honest, the reason, I bet, I can get away with spontaneous developments is because of all the planning I do. The world my characters live in for both series has elements dating back fifteen years ago, even more. I use practically everything I've ever thought, written, drawn, believed and then based on all that, I keep building and reflecting, using them all to form the layers of context and diversity of my characters and their world.
For both series, I've ingrained their premises in my head, writing summaries of them, notes, a synopsis over and over again until I have the essence and it makes sense. Even if I can see the logic and reason, or if it feels good and nice, these aren't the feeling of rightness. I pursue the sensation of harmony and alignment. There is a rhythm in words, a flow to the story, the natural reactions of characters and an atmosphere. If it doesn't feel right, it's not right. And as I try to define the premise over and over again, there are moments that become fermented in my mind. Any book on writing would tell you that such moments are the climax, the mirror moment, the epiphany, and things like that but I don't like seeing them as anything special or important, otherwise I get impatient and it becomes drama for drama's sake, which is really annoying. I keep these moments in mind but I wait, from scene to scene, for such a moment to pass and be missed, cause then it will grow and become something else. And honestly, it's a thrill when you, the writer or reader, see something the character has always wanted, yearned for or needed being dangled right in front of them and they miss the chance. Makes me swoon when it's done right and by right, I mean there's a valid reason the character missed it or intentionally denied themselves from having it.
I don't plot for episodes as you probably got by now, and episodes may link together to convey a single scene. If they link together, there's no need to consider in-between. If at the end of a scene, I always think of the most logical next step. If my character has nothing to do, find out or run from, and none of the other characters have anything to do with them, something went wrong but if the rhythm is right, then I'm missing something. If the episode is too emotional and I can't justify it with evidence, I redo the episode.
For the whole series, or arcs, since I'm a pantser, it only works to know the rhythm of the ending or transition. In writing books, they'll tell you to think of the ending scene, the opposite state to reach, the flaw to be fixed, the misbelief to be corrected, the desire to be met, or your answer to your theme or motif and while these are ways to think of the same or similar things, for me, every character has their rhythm. It's their voice, their manner, their preferences and interests, their history and opinions, which becomes a rhythm in the words that I use to describe them, the dialogue that's written for them, and the pacing that they follow. But it doesn't mean I know everything about my characters. Most of the time, it's my discovery too what a character's preferences or reactions are. Regardless, they have that rhythm. As long as they follow that rhythm, their choices, their decisions, their emotions and reactions will resonate. It has the feeling of "True." So when I plan, writing and editing over and over again to get the essence of the premise, I look for the change in a character's rhythm. It does nothing for me to know that my character will have that thing they've always yearned for or learn such-and-such lesson or fix this flaw and amend that wrong. When a person has changed, how do they talk differently, how have their movements changed, what's their pace, how do they see the world, what do they look at? And from this, are they slower or faster, do they stutter, do they pause, can they smile, will they scream, do their thoughts race or do they see grand and beautiful things? The rhythm in viewing a magnificent sunrise or rising over the hill to behold a sprawling oasis is quite different between a person who appreciates it and a person who doesn't. And readers can tell. If they can tell when a writer isn't interested, isn't it the same that they can tell when a character is bored, resentful, awed or scared?
Wow, this became rather sensational. And I know it doesn't very well answer your question. I mentioned writing books before. None of these methods work for me but I can suggest a few: Story Genius by Lisa Cron, Just Write or Write Your Novel From the Middle by James Scott Bell, and Take Off Your Pants by Libbie Hawker. There's plenty more but these three really stood out to me. I really had hoped once upon a time to be a plotter. Drafting plans is part of my day job and I'd like to believe that I'm good at it, cause it works for other people, the only problem is I'm not good at following it for myself. For any of you who want to know how to not just plot a story but how to think and understand story, these books are good. Take Off Your Pants is the fastest to read. Story Genius is very insightful. James Scott Bell was taught in my creative writing class and I liked the book, not the class. Hope these help.