" From your “due date” calendar, write down a weekly to-do list of twenty or fewer key items. Each night, create the next day’s daily to-do list from the items on the weekly to-do list. Keep it to five to ten items. Try not to add to the daily list once you’ve made it unless it involves some unanticipated but important item (you don’t want to start creating endless lists). Try to avoid swapping out items on your list. "

― Barbara Oakley , A Mind for Numbers: How to Excel at Math and Science (Even If You Flunked Algebra)