How to plan a day
Pick your three most important tasks the night before, while today is still fresh and tomorrow is still abstract. Morning planning competes with morning energy, and the plan you write at 9am tends to be the plan your inbox wrote for you.
Put the hardest task first. Difficulty does not shrink by waiting, and the easy items expand to fill whatever room you give them. If the first task scares you a little, that is usually the right one.
Keep the list honest. A plan with nine items is a wish list, and finishing four of them still feels like failure. Three real tasks plus the appointments you cannot move is a day you can actually finish, which is the point: a plan you complete teaches you what you can commit to next time.
Close the day with the review box. Note what got in the way while you still remember it, then set up tomorrow before you shut the laptop. See the research notes for the studies behind hardest-first and closing rituals.