'Elf' is general term to describe a creature that is in tune with the magic around it, yet maintains a physical body and is capable of interacting with the physical world. Other than that signature feature, the difference between elves and humans is very little.
Anatomy & Morphology
Elves are human in shape, though their facial features are generally much sharper than a human's. Most elven species stand only slightly shorter than humans. One of the easiest way to differentiate an elf from a human is by their ears. Elves possess ears that are pointed.
Growth Rate & Stages
Most elves grow, mature, and age at the same rate as humans, with the exceptions being the Etir and Igna elves. The Etir live essentially 'forever', though their ability to function deteriorates over time until they are unable to think or act in any way. At that point they are only technically alive. The Igna on the other hand, live for an awfully short time, averaging around forty years. All Igna die on the date of their birth, unless they are slain by another force, be it disease, starvation, etc.
Ecology and Habitats
When an elf is born, their body is changed based on the habitat they were born in. A Sola mother may give birth to a Drowis child if the magic in the area is dark. Certain magics congregate to certain areas. Dark will naturally be where there is little or no light. Fire magic will linger around human settlements, who radiate with fire magic. Sun magic is wherever the sunlight touches, as such, there are many Sola. Earth magic seeks high altitude and rocky places. Wind magic travels wherever it pleases, as the wind itself does. Water magic rests with the sea.
Dietary needs and habits
Elves are omnivorous, just like humans, though elves require a significantly higher amount of sugar in their diet. To a human, elven food is unbearably sweet.
Perception and Sensory capabilities
Elves have not particular advantage in any sense, in fact, elves may have slightly worse sight, hearing, and smell. However, they make up for this with a sense that is unique to their species, the ability to sense magical energy in the vicinity. This ability makes it much easier to harness magical powers. However, they are still blind to psionic waves.