A reader asks how I get past the page-40 sucky point.
Simple. I just keep writing. I tend to turn off most of my critical faculties when I'm writing a first draft. I don't turn off the part that tells me whether a scene is good or bad. But I rarely second guess my outline, which I've pummeled a great deal before starting to write pages. I just try to get the script done. Then I can go back and rip it apart again -- after I've seen what works and what doesn't.
I think the 40 page sucky point has more to do with the process of writing than a habitual flaw in my outlines. It's just the point where you've exhausted your initial blitzkrieg, and now you're in the slog of winter war. Once you get past the halfway mark you can start to feel you're on the home stretch. But around page 40, all you can see is miles of second act steppe, with nowhere to get a warm bowl of soup.
It's important to be willing to rip things up if they don't work. But it's much more important to finish things. If you don't finish things, you don't really know if they work or not, or what kind of fixing they need. So I just keep writing until I've written FADE OUT THE END. I make a point of not reading the script before then. Oh, sure, if I realize as I'm writing a scene that I need to set something up earlier, I'll put the setup in. But that's surgical. I won't read the first 40 pages as I'm struggling with page 41. That way lies madness.
Then there's about a week where I'm afraid to read it. Then i read it, and start the long, long process of tinkering and rewriting and tinkering and rewriting. But there, at least, I have a completed screenplay, and I know I'm going to keep making it better, so emotionally it's much easier.
That's me, anyway. The key for me is having a detailed outline you feel confident in when you start -- even if you no longer feel confident in it once you're into the second act -- and just proceeding on faith until you've got a draft.