All elementals possess certain properties that distinguish them from the immaterial spirits. They are beings of the substance of the world, and so they are more deeply connected with it. Elementals have the universal qualities described in Exalted pp. 295-6.
It is always obvious what element an elemental is aligned with; they possess distinctive physical traits and quirks of personality. Some of these are discussed in Exalted p. 295; you are free to make up others.
Physical elemental traits are intrusive and difficult to conceal; a green-haired ondine will find that hats, no matter how well fastened, slide off her head almost immediately. The cold fingers of an air elemental will speedily rime his gloves with frost. It requires an appropriate Ability roll at a difficulty of the spirit's Essence, combined with supernatural disguise techniques, to suppress these characteristics. Perfect disguise effects are not required to make a roll.
Elemental signs that are personality traits are inalienable parts of the spirit's nature; it is impossible for the spirit to resist indulging in their associated behaviours. A gluttonous fire elemental will never leave a table until he has eaten everything there, and will not be easy to take away. An elemental that is restrained from indulging his tendencies will become increasingly agitated and hostile.
As a general rule, elementals possess one elemental sign per Dominion; the sign generally reflects the nature of that Dominion.
Similarly, elementals have a number of powers based on their elemental Dominions. For each obviously elemental Dominion, the elemental possesses an elemental power that reflects that Dominion. For example, a spirit whose Dominions were Salt, Breeze, and the West would have two elemental powers; the West is not sufficiently elemental.
Generally, using an elemental power is a simple action that requires a Willpower roll at standard difficulty. No elemental power lasts longer than a scene.
An elemental may choose powers from this list: