woa i never thought of my angst as good that means a lot
here comes a long-winded answer:

the logical component is me thinking about the story's theme in order to not get off track, overly angsty stories can result of too many different feels for a narrative to handle without any connection instead of emotions stemming from an underlying conflict at the root of it all
general thing but i plan scenes around what info must be conveyed to the reader and how these charas communicate this info in the context, i still struggle to balance show and tell but the idea is to exposit in-chara
(eg. migo and sui dodging each other's direct questions because emo-tion but revealing things via small talk) i make sure their actions and behavior are consistent with the above and who they are to the best i can, imo no fan characterization will be perfect

aside from that is the "vibes" its cliche but i use thoughts and feelings i have experienced before. it can be hard to put uncomfortable feelings into words but words can also blanket the topics to be palatable

hope that all made sense lol