Here's another one ...
Every task has a beginning and an end.
Don't drop the task or imagine it finished before it actually is.
One of the most common occurrences of this happens with what I call 'adult homework.'
When you finish a call or a meeting with someone and your follow up involves sending along additional or clarifying materials, take the time as soon as the call or meeting is over to gather those materials together and send them.
That's the actual end of the meeting -- not when you log off, hang up the phone or walk out of the door.
If you need to put together a proposal, as soon as you're back at your desk, schedule an appointment with yourself to complete that task.
DO NOT add writing the proposal to a list of unassigned tasks that you keep running in either your mind or on random sheets of paper or a post-it stuck to your computer monitor.
That would just be creating more work and stress for yourself. And no real deadline for delivering the goods.
If you struggle with feeling like your 'to do' list is never ending and that you're surrounded by too many loose ends, this behavior may well be part of the cause.
So going forward, when scheduling meetings, you'll now want to begin budgeting enough time following a meeting to allow you to finish whatever homework might arise as a result of that meeting.
Or at the least to create an actual appointment with yourself when you will.