I agree with the above answer, but want to help simplify it for you.

You've got "jealousy" and "racism."  These are themes.  If I were you, I'd pick ONE.  Make that the main focus of your essay.  Then, show how the author uses three literary elements (choose from the list provided in the first answer or follow the link below for a huge list) to develop this theme.

A sample thesis statement might sound something like: "In Big Black Good Man,  the author uses __________, ___________, and ________ to develop the theme of racism." (*The blanks, of course, are the elements you will focus on.)  I'd actually encourage you to say more than just "racism."  What is the author actually trying to say about racism?  This part of the sentence should probably have a bit more detail.

Then, each body paragraph proves how one lit. element develops the racism theme.  This way, the focus of the paper is cohesive (one theme) but multi-faceted (three elements).

You are on the right track.  'Literary' elements include about everything you can think of in a written piece:

the theme of the story (like 'revenge' in Hamlet, for instance);

the story line or plot (what happens to whom and why);

the setting (and this includes both the physical setting and the time or period in which the story takes place– along with the customs appertaining);

the characters (both their created personalities and the way in which the author portrays them);

the author's viewpoint on any of these;

the literary techniques and devices that the author uses to create his piece and express his viewpoint;

and the overall impression that the finished work makes on the reader– its genre, its message, its art.  This last to me is also a literary element... or at least the cumulative effect of all of them!

Generally, a good thesis and its statement will incorporate at least two and probably 3 of these aspects:  "A interacts with B to create C for the reader" is one common template for utilizing three literary elements.