Mostly I just don't manage. I write non fanfiction stuff too and I've got too many projects, ideas, etc. I'd say it might be the adhd or autism tendencies that make it really hard for me to stay focused on a project for a long time, too. And just a general lack of time plus energy whenever depressive phases hit me.. I'd love to finish them all of course but I reason to myself that it's projects I do for fun so I should do them in a way that's fun to me /doesn't pressure me instead of focusing too much on the end result of getting them finished. It's why I've got a lot of one shots too because it's easier for me to finish if I keep the story ideas short and limited in my head instead of wanting to create those big novel kind of stories... Hope that explains it a little bit