Create a project for each client or engagement. Everything for that job lives inside it: deliverables as tasks, steps as subtasks, small chores as leaves. Collapse the projects you are not working on today and the list stays short.
Each project shows its own progress percentage on the Projects screen.
Break a deliverable into subtasks until each step is a single sitting.
Set progress as you go, so a draft that is 70% written looks 70% written.
Drag a task into another project if a piece of work moves to a different job.