By grit and willpower mainly. If your family doesn't instill these values in you, then you will have to get pretty lucky to come up with the tools to get by in this world. 
 Fun Fact from this book: 
 GPA is a much better predictor of lifelong success than SAT. 
 SAT you can be really smart and take a test one afternoon because you really need a good number. But that's just one day. A good GPA is every day mountain of evidence of your effort. Without the effort you can't get much done unless you are a genius and more than likely you are not. 
 This book read like a documentary focusing on individuals and a single school per chapter. It doesn't pretend to know all the answers but it lays out some pretty compelling stories that make you want to get up and accomplish something.