The waters
The imagery of water is a dominant feature of the Enuma Elish. The waters have always existed, and are encapsulated by their divine representations, Abzu (fresh water), and Tiamat (oceanic water). The imagery might be seen as a metaphor for chaos, which would be consistent with other imagery from the ancient near-east.
Serpents
Dragons and serpents are another dominant image offered in the Enuma Elish. Like the Hebrew Torah, the imagery of the serpent is an effective way to evoke a sense of supernatural, preternatural forces. The gods are not depicted as primates like the humans are, but rather, many of the gods have animalian forms, the most common of which is in fact a serpent or dragon.
Fire and lightning
To say that Marduk's elemental powers of lightning and fire are 'good' would be to misunderstand the Sumerian view of morality. Rather, they can be understood as supremely powerful. Fire has been used in ancient literature as an indication of supreme divine power. See, for instance, the Greek story of Prometheus, or the Judeo-Christian depiction of hell. It is likely that a similar worldview produced the Sumerian account of fire being the only force that could conquer Tiamat and her chaotic waters.
The heavens and the ocean
Perhaps the most central, meaningful imagery offered in the Enuma Elish is the descriptive account of Marduk slaying Tiamat, which corresponds to the creation of the blue 'waters' of the heavens, and the air that separates them from the earth. Another way to view this imagery is that air and wind were the elemental consequence of the divine conflict between fire and water. That is, the live-giving force came from the electricity defeating the waters to make the four winds.