Use the calendar function that goes with your email or any other calendar to track assignments, extracurricular activities, other jobs and tasks, and send yourself reminders of everything things you intend to do. It is worth the time to input things.
I know that every single student has forgotten an assignment at least once in his/her life. If you continually keep track of everything, it’ll reduce the chances of losing a few points.
Who cares about a few points? Well every student hits a point where he/she could have gotten that grade a whole letter higher if not for a few points. I remember when I got a B+ by 2 points. If I hadn’t forgotten some homework, I would have gotten an A.