Probably the best thing to do is write on a yellow pad--or whatever you plan on--the elements of Aristotle's definition of tragedy, specifically the tragic hero.
- The tragic hero is a man of noble stature
- The tragic hero's kingship/royalty is also a symbol of his initial good
- The tragic hero is good, though-not-perfect, and hsi fall results from his committing "an act of injustice" (hamartia) either through ignorance or from a conviction that some greater good will be served.
- The act is a criminal one and the good hero is still responsible for it.
Once you write these definitions down and lay them out before you, find the appropriate defining moments or incidences when the hero of each play exhibits a defining trait of the tragic hero and write this example in the second column for Macbeth or the third column for Hamlet alongside this defining element. You can, then, evaluate Macbeth and Hamlet by looking at how they fulfill the definitions. With the use of this information you can write the comparison/contrast essay.
Also, the best tragedies have organic unity: the events follow not just after one another, but because of one another. Find what this unity is.
In addition, the best tragic plots involve a reversal of fortune or a discovery (a change from ignorance to knowledge or both for the tragic hero. For instance, Macbeth's "tomorrow and tomorrow and tomorrow" speech in which he recognizes his "vaulting ambition as the cause of his many murders is such a discovery. In "Hamlet," the Prince of Denmark fianlly spurs himself to action when he sees how willing Fortinbras is to risk dying in order to fight the battle against Norway.
Personally, I find Hamlet much more noble in heart from the beginning than Macbeth is in the beginning of "Macbeth." For initially "Macbeth," seems more cruel than noble in defending Duncan's kingdom is brutal as the captain describes
brave Macbeth--well he deserves that name--/Disdaining fortune, with his brandished steel,/which smoked with bloody execution...(I,ii,16-18)
while Hamlet ponders long whether he should avenge his father's death by regicide. (Read over Hamlet's several soliloquies for insight into his character.)
For pointers on how to write a comparison/contrast essay, check out the sight below as well as the character analyses.
Good luck--The planning out of a comparison/contrast is paramount.