The PARA method on a task tree: projects, areas, resources, archive
Tiago Forte's PARA method sorts everything into Projects, Areas, Resources and Archive. How it works, and how to apply it to a nested to-do list.
Articles about tags
Tags vs folders: how to organise a to-do list without overthinking it
Folders give tasks one home; tags let them belong to many views. When to use each in a to-do list, and a simple setup that combines both.
Getting Things Done with a task tree: a practical GTD setup
David Allen's Getting Things Done, explained plainly, and how to run it on a nested to-do list: capture, clarify, organise, reflect and engage.