Took this course in college. Don't remember much about it except the professor would offer extra credit because he thought no one would ace his tests.
I regularly got 105/110 on his tests, so one day he calls me in and asks, Andrew, how much do you study per hour of class?
You were supposed to study 2 hours for each hour of class. I really don't know how I measured up to that, but I said to him, I study until I know it.
He looked at me like I was some kind of smart ass trying to impress, but really its what I did. Never really thought about it before then, but that's actually the golden rule.
Study until you know it. Then you know you are done.