Create a Not To Do list....
Put it as first page in your binder, planner, phone, etc. Review it as part of your daily kickoff routine (15mins min) as you're making your "To Do" list for the day. Empower yourself to say No if it's on the "Not To Do" and either delegate or destroy the task.
I'd be happy to talk further about a regular "15 Magic Minutes" morning routine.