I can say I am an extremely organized person. My schedule is PACKED from trying to keep my grades up, dance classes, piano recitals and concerts, running my nonprofit business, clubs, and volunteering.
Make Google Calendar (or a similar productivity app like Notion or Apple Calendar) your best friend. Put all important dates, due dates, plans, or anything else you have to do. I recommend Time Blocking, which is assigning specific chunks of time to each task, instead of just writing a to-do list. Using Time Blocking specifically for studying (see example below) helps you stay focused and, more importantly, avoid procrastination. For example, instead of just saying you're going to study chemistry when you get home, actually write out the time that you're going to study.
Being organized doesn't just save time, it lowers stress and gives you more time for things you actually enjoy! Below, I've made a list of things you may want to do before school to get more organized.