
Hey Anna, two things make inbox zero stick for me — a simple routine and a few rules that sort before I ever see most mail. I triage twice a day and treat the inbox like a to-do list I do not write in by hand. Anything that takes under two minutes gets a reply then archived. Anything longer becomes a task or gets snoozed to a specific date and time, like tomorrow 8 a.m. or next Monday 8 a.m.
I keep one label or folder called Action for stuff I must do and one called Waiting for things I am expecting a reply on. In Gmail I turn on Send and Archive and keyboard shortcuts so I can hit y to archive or s to star without the mouse. On iPhone or Android I set VIP or starred senders to notify me so I do not miss the truly important messages while everything else stays quiet.