I've been writing since I was 13 and the most successful pipeline I've found for myself is to have a little bunch of text docs in which I write themed elements. I'll have a doc for plot devices that I think would be useful, one for emotional sequences I want my characters to experience, one for events, several for listing characters, locations, factions, cultures, beliefs, politics, etc... And then I start to thread all those things together in another doc so to shape the skeleton of the plot, with milestones.
Then I write the script in the fashion of a theatre play, with annotation as to where the focus should be, and trying to already picture in my mind how I will organize the page.
HOWEVER, for my current series, Singmire Haze, I just have a small list of little things I'd like to have in the story at some point, and for the rest it's just improvisation. I usually don't know what will happen beyond the 5~10 next pages, so it's a lot of fun.
But also something I can achieve thanks to those 13 years of experience in writing. Heh. Now I can say I've been writing for half of my life.