The Greek gods have human characteristics or are anthropomorphic. Anthropomorphic, means that they take on the shapes and characteristics of men. Gods are born and created the same way people are. The first generation of gods basically represented the universe and the earth. The second set of gods were the titans, which basically represented the elements of the earth: wind, water, fire, etc. The third set of gods were the olympiad gods and they defeated the titans and controlled all.
The Greeks also practiced hero worship who often called demigods. Demigods were generally the offspring of humans and gods. Like the Egyptians, the Greeks practiced syncretism, combining similar gods from other cultures into one. When the greeks meet a foreign god they liked they would combine it the closest matching greek god.