I came to realize that with everything I'd written on characterization and creating characters, I had nothing that covered the basic process of character creation and development, nor the basic structure of what makes a complete character - in short, basic character creation and development theory. So, here are the general processes I used to develop and create well-rounded characters.

The Character Creation & Development Process

This flowchart depicts how the character creation and development process usually works for me. Basically, it's an ongoing cycle of development, testing, and refinement that doesn't end until the story does.

The Anatomy Of A Complete Character

Generally, I divide the basic structure of a complete character into five points:

Your character’s psyche - xir personality, attitude, ambitions, hopes, and fears, as well as why your character thinks and feels the way xe does now (which would include your character's history, upbringing, and all that). The challenges your character will have to overcome, and the flaws or difficulties that will set xir at odds with others. What makes your character desirable to have around and why others would choose to associate with your character excluding your character’s special powers, talents, or physical appearance. What your character is without being in a position of power or having supermagical powers. Your character’s talents and skills, and how xe uses them. Your character’s physical appearance.

Now, let's liken all that to a vehicle.

The first item, your character’s psyche, would be analogous to the engine. If an engine is missing crucial parts, it’s not going to run. If your character has vast holes in xir psyche, xe’s going to be virtually unplayable because all you can really do is default to “stall and idle until someone with a better engine takes mercy and tows me somewhere.” Stalling occasionally is okay and can add dramatic potential, but who is going to want a vehicle that has to be towed even to the grocery store?

Two would be analogous to a car’s flaws. Pretty much vehicle has its weak points, either through design flaws or wear and tear. In-universe, this is okay because flaws add dramatic potential and challenge for your character - a race car suddenly starts smoking in the middle of a race? That’s dramatic and suspenseful. Of course, you don’t want your character to be so flawed that xe’s basically a lemon - nobody’s going to watch a race car that can’t even get past the starting line.

Three would be analogous to the interior. People probably aren’t going to want to drive or ride inside a car that smells like cat urine and has springs poking out of the seats unless they’re really desperate and/or have no other alternative, and the minute they have an opportunity they'll probably try to find a replacement. On the other hand, a clean and comfortable interior might make someone willing to overlook the fact that the car is painted a horrible shade of green, or doesn't accelerate quite as fast as some other cars. (Now, this is mainly important if your character is supposed to be a hero, or at least a sort-of hero. If your character is a villain, then being a generally despicable person all around may be appropriate.)

Four would be analogous to the wheels, suspension, and steering system. Without these being functional, a car is useless because even if the engine is in perfect working order, it still can’t go anywhere. Of course, your character's talents don't have to be exceptional if the story doesn't call for it - you don't need a mountain-worthy suspension system to get you to the grocery store, or a Formula 1 race car's speed to take a cross-country trip. Your character just needs the skills and gumption to get something of dramatic value done, whether it's the determination to keep looking for a lost loved one or the skill to hack into the evil overlord's computer systems to shut down the doomsday device.

Lastly, your character’s appearance is analogous to the car’s body. It’s definitely a good thing to have, but at the end of the day spots of paint or even huge chunks can be missing from it and everything else will still run. In other words, we don't need to know how many hairs your character sports on xir left big toe. On the other hand, a car with a gorgeous paint job and perfect detailing is going to be useless if the engine and wheels/suspension/steering don’t work.

Just like vehicles, characters can and should be tweaked and modified if something isn't working out. Don't get too attached to your character being one specific way, especially early on in development, because you'll often find that something you initially thought of won't work out as well as you'd hoped.

I strongly recommend that during the early stages of development you priorities the items in the order which they appear on the list - worry about your character's history and motives before skills before appearance. That said, if you're working on history and motives and something comes to mind for your character's looks or skillset, go ahead and write it out or toy around with it for awhile. There is no "correct" order so long as you end up with a well-developed character in the end.

We can take all this and sum it up in an acronym - POSTA: Psyche/Personality, Obstacles, Sociability, Talents/Tools/Toys, and Appearance, summed up and explained in the below image: