Another good piece of advice was to think about the hierarchy of characters: who's the most important one? Then you can make decisions about interiority, or how deep the POV goes. Like Flournoy explained, with the main character you get lots of information about her problems, how she thinks, backstory. So basically the big existential issue that the character is struggling with, which probably has something to do with your theme. The main characters have the most character development and the reader expects their issues to get solved during the narrative. For secondary characters, you probably get some interiority, but not as deep as for the main characters. They can also have issues that get solved, but they're probably less complicated and can maybe be resolved in a few scenes, and the reader expects them to get solved before the main character's issues, which are the most important things in the story. (So these are probably the side plots.) For tertiary characters, it's enough to give a few memorable details, but in their POV you don't really have to go into their issues (it's enough that the reader imagines they have them, that they're real people), but usually they're used to convey information about the main character you couldn't convey from the other points of view.
It's also important to apply the idea of the hierarchy to the level of conflict you assign to a character. Flournoy said that the primary characters get the big, existential, difficult questions,like 'who am I?', 'what do I think about how I'm living my life?', or 'what's my relationship to religion?'. For the secondary characters they can be a little less existential, maybe a bit more concrete, like dealing with teen angst. For the tertiary characters, the only conflict or issues that have to be resolved are the ones that have something to do with the main characters.
Rebecca Maccai talked about acting and how it can help you understand writing, a really interesting lecture. She talked about how every scene and character has to have a purpose, and that you should think about why you feel the scene is important. If you took the scene out and the story wouldn't make sense anymore, then the scene is serving a purpose. If your reason for keeping it is that you like it, worked hard on it, or maybe that it shows what a character is like, then it isn't essential. A good scene should do multiple things. She also talked about backstage decisions, which amounts to the writer knowing what's going on, the motivation of the characters, and also having done her research. You don't need to put all this on the page, so no info dumps, but if you haven't made the decisions, it shows as a hole in the story and makes it feel implausible. Another interesting idea she presented was that you can use the character's fears to inform these backstage decisions. They're linked to the character's desires, after all. She also reminded us to think about character physicality, so basically not to use the same tired physical gestures when you're using action beats instead of dialogue tags. These are an opportunity to come up with something that reveals something about the character to the reader.
Margot Livesey was our third lecturer this week, and she talked about picking the right POV characters and exploring your options. Sometimes the reason a writer gets stuck with a story is that the POV she chose doesn't work for that particular scene or event. Sometimes bringing in another POV character can help.
This week's writing exercise was tricky: we had to use a group of three women at first and then bring in a fourth one and write about how her arrival shattered the status quo. We were supposed to just come up with characters and their motivations and not think about plot, just let the characters do what they would, but my brain just refused to work like that. After two days of drawing a blank I gave up and wrote the opening to a short story that I've been thinking about for a while. Guess I'm not pantser material, then?