An organisational system (or metasystem), “Getting Things Done” (GTD) focuses on contextual “next actions” from a list of active projects. It was created by David Allen.
Allen suggests grouping tasks into projects, assigning context (e.g. @home, @work, @out) and breaking tasks down into individual, actionable tasks called “next actions”. The idea is to determine tasks on a “just in time” basis, then act on them.
I use Todoist as a GTD-supporting tool.