Deadpan has an entire point-by-point plot sheet, detailed like this, for example:
-> flashback #1: knoth in mall
- acquires meds
- taunts faceless
- chased out of mall (no ammo)
- runs to house, fence hop
- meets D (from behind)
then, in another page, i have more details for when scenes require a bit more dialogue for example:
- runs to house -> into kitchen -> faceless get in -> "whatever you do dont look round"
and in another page i have a list of everyone's secrets and when they'll be revealed, plus chunks of important monologues that i need to remember to put in at some point in the plot...
but most of the detailed planning comes when i'm doing the thumbnails, because that's when i'm deciding exactly how and when and where to show the story unfolding. all that other stuff is really just to keep me on track, since with such a longform narrative comic you could easily slip off (and im sure i would have, given my forgetfulness)!