By watching student's 25 years younger passing exams without actually studying them (if I'd do that, I'd bascally failed; I've tested that approach :-))
For example, I went to school for a video game programming/design B.Sc. First couple of years were super basic programming to get non-programmers up to level, so to any of us who programmed since gradeschool it meant no studying/effort for a year while we breezed through simple loops/conditionals/Java stuff.
Obviously, things cranked up a notch when we finally got to new material.