This seems to be an extremely personal task. I think that the best way to answer it would be to flip it back on you. In doing this, I mean to ask you, straight out, what were your thoughts about the book? Did you like it? Did you like how Fitzgerald showed the characters? Did you think there was a sense of justice present or a lack of it in terms of the ending? How do you think the men and women were shown in the novel? How about the rich? In the time that he was writing, there was an extremely wealthy section of society and everyone sought to be in that upper bracket of “flapper society.” All of it was disrupted in the 1930s with the Great Depression. Do you think that we still have a type of social order like that today, or are we more along the lines of the people in the 1930s that experienced economic distress on a wide scale? Along these lines, how do you think money was shown in the novel? Do you agree with this conception of money and wealth shown? I think that any or all of these topics could be very good starting points to determine your own impression or reflection of Fitzgerald’s work.
I am not sure what you are asking, but I think you want a reflection on the novel, The Great Gatsby. If that is the case, I will give you my opinion. Having taught the novel for many years, I came to see this as one of the greatest American novels. Why? The novel has greed, betrayal, lust, innocence, bigotry, classism, love, hate, hope, despair and so much more packed in it. It is the equivalent to modern day soap operas but written in a way to cause the reader to think about modern values and whether all that glitters is really gold. So, if you are being asked to reflect on the novel, think about the lesson the author wanted you to take away from reading it. Can we go back in time and try to recapture a love once lost? Is having money and "things" the key to happiness? Are there different rules for the wealthy? These are just a few of the issues raised in the novel. Your reflection should be what the book made you think about and how it caused you to question or strengthen your beliefs.