Scott Fitzgerald put facets of himself and his life into many of his works. By using his knowledge and experiences he was better able to develop characters and setting, and put personal emotion into his work. Many things from his novel, The Great Gatsby paralleled things from his life.
Fitzgerald used himself and people in his life to characterize people in the novel. He based a lot about the character Gatsby on himself. Fitzgerald wanted to be a war hero in World War, so he made Gatsby a war hero in the novel. Gatsby worked on Dan Cody's yacht after Daisy married Tom. This parallels Fitzgerald working on a boat when Zelda broke off their engagement. Fitzgerald might have used his parents as an inspiration for Dan Cody. They helped him be a part of the upper class by sending him to a private school full of wealthy children and telling him how people of the upper class act. Dan Cody educated Gatsby on the mannerisms of the upper class. Fitzgerald based the character Daisy on his wife Zelda. He characterized Daisy as rich and popular, like Zelda was. The two were engaged, but Fitzgerald first had to prove he could support her. Daisy dated Gatsby, but wasn't allowed to marry him because he wasn't rich. Fitzgerald put some of Zelda's own words into the novel. She said that she hoped her baby would be a beautiful little fool, and he made Daisy say this in the Novel. Fitzgerald could understand what these characters' emotions would be and how they would act in the situations he put them in better because he based them on the people he knew. In turn, this helped him to develop the characters better.
Fitzgerald used familiar places and scenery from his life to help him with setting in The Great Gatsby. Fitzgerald's father lived in Minnesota, and Gatsby grew up in Minnesota. He used his knowledge of how people behave there to characterize people from the same place in the novel.