* Have zero friends
* If they want to follow you, they can subscribe you.
* Subscribe to friend(s) you wish to follow
* Join group(s) you feel you must follow. Could be your classmates.
* Turn off all notifications
* Those public groups, no need join. You can read them when you like.
Truth be told, this is just a theory. I have trouble joining Facebook since I deleted my account. I could create a new one using a different email ID but I refuse.