Everyone is in need of some organization, and Google Calendar is a great place to find it. Organize your life in a quick and accessible way--and wait as a huge weight will be lifted off your shoulders when you realize that your brain doesn't have to keep track of so many things.
Organize your events by color.
This will help a ton when you're skimming over your day's plans. Separating it by school, work, family, friends, bills, and etc. will help a ton.
Include the location of the event if you think you might forget/need to quickly navigate your way there.
I work at a business that has four locations and often forget which one I'm at on which day... this makes it a lot easier to keep track of.
Share your calendar with the people that need to know.
They can access it from their own devices without having to interrupt you in class or at work. If you didn't answer the phone, they can quickly check to see if you're busy before they jump on you for not answering!
Create separate calendars so that you can have a personal one and one you can share.
Not everyone needs to know EVERY detail of your schedule. Google Calendar is the best way to have everything available for you to see while also keeping others in the know--but not too in the know.
Set reminders for events you fear you may forget.
For appointments and other important things that aren't regularly a part of my schedule, I set extra reminders just to be safe. I usually set one for the day before just so that it's at least on my radar and there's less of a chance for me to forget it.