Time blindness means an hour feels like ten minutes, or the other way around. Paper tools help because you can see them without opening an app.
Draw the day as blocks and shade what's already taken. The empty space you can see is your real time.
Write how long you think a task will take, then what it really took. After a week you'll know your personal multiplier.
Keep three tasks in view and the rest on a separate list, so the page doesn't overwhelm you.
Want all of this ready to print? The Low-Battery Day Planner Kit has 14 pages (US Letter + A4).