It's been a problem all my life. I get involved in something I really like and like a funny car on a track a half mile too long, I run out of fuel before I get to the end. That, or I see a newer, shinier story and gravitate to that like gold diggers to a lottery winner. End result - nothing gets done.
Lilith and Eve... something that fell into my lap.
This screenplay - Aethyrika, (pronounced ay-theerika) is the closest I've ever come to finished in my screenwriting. The first draft was - well, a first draft. When I put it out there, it got pretty good reviews, but had holes in it... a few flat characters, things that didn't relate, and unfilmables. My biggest problem - as a story writer, I write like a movie, but that doesn't translate the other way around. Back to the board.
The second draft was a lot more concise and clean, and though the holes were patched, a few still leak. The movie name is based on a pagan tome. Hmmm... guess I should explain it somehow... something I am doing in this revision. The antagonist was something I picked out of light research... but her background turned out to be a gold mine. But how much can I use? Moreover, since it crosses religious lines and the tome in based in Celtic Paganism/Christianity - how many people am I gonna piss off? I was able to answer that easily enough. Not many. In fact, there's more than a few people intrigued by the roots of the book... but that's not the story, it's just a vehicle within it. The name - I made it up. It doesn't exist. I didn't want it to be tied to anything genuinely historic, other than what I can control. I love being a demigod...
Originality is a big challenge, too, especially in horror. I don't want a "place your bets on who gets killed next" kind of story - that's not something that draws on your fear. I'm looking forward to getting deeper into this revision, as long as the research doesn't have my mind wandering off... okay, that's already happened. But I'm trying to contain it. But... those shiny new ideas are knocking... and they're bringing notes.