I'm about to tackle some of my first personal projects that I've had in the queue and are trying to be so organized about what I can be about it. As I describe the project, I wonder what the best tool / app would be to track these details, such as core functionality, features it should have, etc. I've tried using pen and paper to outline the app, but I have found it not really for me. I have shocking handwriting, I always find that I will rework things after I have written them and I must keep my notebook with me at all times if I think of something I want to add to the site.
I've found myself lean against the Notes app on iOS because it's simple, easy to use, and it automatically syncs over my phone and computer. I have also considered other popular programs and tools such as Evernote, Things, Todoist, OneNote, etc. Some of them seem appealing, but I'm not sure if they offer enough for me to pay or have to install another program on my devices.