I think the general consensus is "plan ahead."
I have not quite finished the script for Burning Bright, but I have written out almost 50 chapters (yeah...it's long!).
For me, I always need to write and plan everything first because it helps with character development and backstory. I want people to read my comic, see something happen and think "Oh, that's why that character reacted that way back in chapter three."
The example I alway fall back on is Futurama. I know it was an episodic show with not an always concurrent storyline, but there's an episode where you find out Nibbler goes back in time in order to put Fry in the cryogenic chamber so he can save the world 1000 years in the future (wow, that sounds weird if you haven't watched the show!). And if you go back and rewatch the very first episode, you can actually see Nibbler's shadow under the table as he pushes Fry back into the cryogenic chamber.
I just think it's cool to know that any story is planned out from the beginning, and that's what I want for my readers if they choose to keep up with the story! 
