The Great Gatsby - A failed pursuer who failed greatly

Recently I read a novel The Great Gatsby, there was a big confusing question for me to understand why Gatsby is great. And after reviewing some comments on the book, I thought I find some points of view to discuss this issue.
Let me summarize the plot in retrospect. Gatsby, once a mundane person, rising from nowhere to an mysterious rich man after joining the army and doing business. But the woman named Daisy he loves had married to an old money several years ago. With the help of the novel’s narrator Nick, who is a relative of Daisy, Gatsby got the chance to meet Daisy again. Myrtle, the mistress of Daisy’s husband Tom, struck to death by Daisy while driving Gatsby’s car in an accident. Myrtle’s husband got insane and shot Gatsby to death after he was told by Tom that the car belonged to Gatsby.
Obviously, the man who made such big fortune must be intellect enough to socialize with people, but when it comes to Daisy, he hardly ever used tricks to attract her. He honestly and carefully handled the relationship, with the woman he only loved for many years, because he always know what he really wants. The saying he receviced from his father, guided him to a considerate and thoughful man.
“Whenever you feel like criticizing any one,” he told me, “just remember that all the people in this world haven’t had the advantages that you’ve had.”
And his lifestyle was rigid and self-disciplined. He arranged his daily activities accurate to 15min, and listed his determinations.
I think that’s what make him great.