My frustration with most task manager is that they require me to manually maintain a parallel universe to the other tools I use to execute a project such emails, files, links, notes etc. This manual maintenance require a lot of discipline and typing. When I am busy I am less likely to update the task list and then few days after that my tasks are out-of-date and it takes even more energy to fix, which I am less likely todo.

As a result I decided to develop my own task manager for Gmail (https://www.centask.com/) a tool that integrates everything I need to complete a project, (emails, files, links, notes etc.) organize it in any way I want it, and schedule single and nested items to appear when I need them. Since it is Gmail centric I can email myself links and notes from any app.

The key for me was that I process my email inbox within Centask so I must use it, so it may get long when I am busy but never gets out-of-date.

When I have paper notes, I either type them into Centask as separate items or email myself an image of it and add the image as sub-task of the main task.

Hope that helps