I've included so far the significance of the time period (the jazz age, post-WWI etc) the importance of the clocks and what gatsby's dream is.
Also why the past is so important, but I'm stuck on the argumental side, and if the past IS in fact more important, or if it just seems that way due to gatsby's character.
Any points or anything would be a help. Thanks.
The past is certainly an important part of the novel and without it, there would be no motivation for the character's actions. However, most of the themes of the novel are developed through the present, especially Nick's observation of the action. We have to remember that Nick is really a major character in the novel and the only character who really learns any lesson by watching the relationships between Gatsby and Daisy and between Gatsby and the rest of the community. He is the one who realizes that Daisy and Tom are "reckless" people and the futility of Gatsby's obsession with Daisy. Thus, even though many of the reasons for the actions of the characters are created in the past, the real lessons are learned by how the characters deal with the past through their actions during the actual time period in which the novel takes place.