Compare a Mesopotamian hero and a Greek hero using specific shared traits and specific differences, rather than a vague overall impression.
Comparing two heroes well means going past "they are both strong" and finding the specific traits, trials, and endings that actually line up -- and just as importantly, the specific places they diverge. A strong comparison always points to concrete evidence from each story, not just a general feeling of similarity.
Gilgamesh, king of Uruk, and Heracles, the great Greek hero, share a surprising amount: both are part divine and part mortal, both possess superhuman strength, and both undertake a demanding set of trials -- Gilgamesh's journey to find Utnapishtim, Heracles's Twelve Labors. But their stories end in opposite places: Gilgamesh fails to gain immortality and must learn to accept death, while Heracles, after his trials, is welcomed among the gods as one of very few mortals ever granted a place there.
Mastery looks like: They can name at least two specific shared traits and one specific difference between two heroes from different cultures, each backed by evidence from the myths.
Common stumbles: Comparing heroes with only a vague overall impression ("they are both cool and strong") instead of specific, checkable traits and endings.