My new novel is complex. Those of you who know my writing probably won't find this surprising, since everything I write tends to be complex and develop extra layers. So I thought I'd share a few thoughts on how I keep that complexity under control.
#1. I outline. I'm not talking about the standard-format Roman numerals and then letters etc. but I will write an outline. If my vision on the story is foggy - which it often is for latter portions of long novels until I get closer in the process of writing them - then I just write down an unnumbered list of critical events that have to happen, in the order in which they happen. Those can include things as big as "X character gets killed" or as small as "Y character makes a decision." The closer I get, the more things start fleshing themselves out into scenes and chapters, and then I write down a general description of what should happen.
#2. I manage my worldbuilding. I design until I'm blue in the face, and compile lots of files full of notes. After mostly finishing the design, I try to wrap this all together into one bundle which I call point of view. Once I have the point of view right, it pulls a lot of the worldbuilding and basic character elements together at once and lets me work with them together instead of separately. As I write, I then selectively deepen my understanding at different points depending on the needs of the story.
#3. I keep explicit track of plot and character arcs. Plot arcs and character arcs often parallel one another, but are not always the same. If there are only two or three arcs going, I can usually keep track of them in my head, but my current novel has about six, all of which are interrelated, so what I'm doing is making a list of them and appending it to the back of each chapter. Then once I've got the chapter sketched, I can check to make sure all the arcs are addressed in the action I'm planning - and again after I've finished writing I can write notes about how each arc has been pushed forward. This is information that I can then carry forward into planning and writing the next section. So as an example, my initial arc list looks something like this:
Nekantor/Speaker of the Cabinet/Garr
As you can see, it's pretty much incomprehensible to anyone but me (and others who know character names or to whom I've mentioned plot elements!). I stick notes on the end of each arc label to track what I've done. Ideally, each chapter should do something for every arc. It's probably okay if one or two of them don't develop through a single chapter (due to the pov character I'm working with) but I want to make sure I don't drop them for too long.
#4. I keep track of characters' mental states (psychology). This is related to plot and character arcs, obviously, but I do track it independently. Given that I place a lot of importance on characters' decisions (related to romantic or platonic relationships or to any other critical plot element), and I like to have my characters build up gradually to those decisions. Motivation is really important - so important to me, in fact, that it's the reason why I write chronologically. What a character thinks at any given point will change what they do, and thus what the story does as well. I can't be certain whether an event will happen - or more critically, how it will happen - unless I have a continuous process of development in the mental states and motivations of the characters and their interactions. If I don't keep track I will have to go back and find the lost thread of psychology where it dropped off, and rewrite everything from then on (which makes me scream and want to bang my head on walls!).
#5. I keep track of "arrows." Literally, this is what I call them; my friend Janice will say to me, "You need to line up your arrows," and I'll know exactly what she means. I'm not sure whether to call it "theme" but I usually have an underlying issue that I want to have going on in a story. The plot and characters tend to serve it on some level; descriptions will also serve it on some level. In my linguistics stories, it tends to be the critical social or linguistic issue that underlies the misunderstanding between human and alien characters - so a good many of my arrows serve as clues to the hidden solution. The arrows can be words, phrases, word repetitions, dialogue elements, events, etc. so long as they contribute to the drive and focus of the story. When I write with attention to arrows (and believe me, I give the arrows a great deal of attention in revisions because they're tougher to track in a first draft), it's not just a question of just finding a cool way of describing something, but finding the right way: the precise description that will align its arrows with the character, the plot progress, the worldbuilding elements, the dominant metaphors, the theme, etc. This may all sound rather abstract and possibly a bit frivolous, but "lining up the arrows" often makes the difference with my beta readers between a story being cool but not having much impact, and a story being vibrant and amazing. Another way to talk about arrows is in terms of "alignment" and "focus." They're worth some attention, because they can make a huge difference.
One last note: I don't feel I have to keep track of all levels at once. I bundle things together to get them going (like pov, which subsumes worldbuilding and character and elements of character arcs etc.). I don't try to keep my outline in my head; that's what the written outline is for. The only part I keep in my head is the immediate section I'm working on. I keep my focus in the character's point of view and develop the plot along with the mental states. I try to keep my arrows aligned on a basic level but if I don't quite manage it on the first go, that's okay. That's what revisions are for!
Those are my thoughts on complexity for today. Now I have to go do some juggling.