"Yesterday is not ours to recover, but tomorrow is ours to win or to lose."
I have this theory about grades.
Grades = (x)(y)(z)(X) where x equates amount of time put into studying where y equates efficiency of studying where z equates a constant known as one's mental capabality where X equates luck.
z is something most people cannot change. We are born with it. X, a.k.a. luck, is something that we can hardly change either. So the things we can really change ourselves are x and y.
Some people just spend so much time studying but get poor results. This is probably a result of having alot of x and not enough of y. The more one of the variable exceeds the other, the more one gets diminishing returns if he or she increases said variable.
For instance: ignoring the constants, let x be 6 and y be 5. If one puts one more unit of effort into refining one's efficiency of studying, one gets x=6, y=6, for a total of 36. However, if one puts said unit of effort into spending more time studying, said person gets x=7 and y=5, for a total of 35. The larger the difference, the lesser the returns.
So basically we have to strike a balance between the amount of time we spend studying and how efficiently we study. Sometimes spending some time to ensure one studies more efficiently is just more worth it, even if it means cutting down on the total amount of study time.
And the extent to which z and X factor in depends largely on the subject[s] involved. But since they lie outside the realm of what one is able to change, one must ensure that the maximum possible results are attained for a given amount of effort put in. Remember to study efficiently. And even if you study efficiently, remember to actually put time into studying. No matter how large variable y is, if x=0 it still amounts to nothing.