They are normally invisible to the untrained eye.
They do think and reason.
They do not normally belong to the physical plane.
They are made totally of their respective Element.
Elementals exist to keep their Element active and balanced.
With that taken care of, let's get
a bit more personal:
Reportedly Seen As: Green Light or "Little People"
Some Behavior Traits: Nurturing and Stubborn.
Duties: Caring for Earth, Material Manifestation, Aiding the Growing of All Living Things, Protecting Animals and Creating Stability.
What Attracts Them: Love For Nature & Life. Anything shiny. Honey.
Reportedly Seen As: White Lights or "Faeries"
Some Behavior Traits: Ever-Moving, Creative.
Duties: Protection of Air, Carrying Out Elemental Plans, Movement of the Air and Wind currents.
What Attracts Them: Incense Burnt For Them, Feathers and Speech.
Reportedly Seen As: Small Flames or "Lizards"
Some Behavior Traits: Explosive, Fast Acting.
Duties: Spark Fires, Movement of Flames.
What Attracts Them: Fire.
Reportedly Seen As: Blue Lights or "Mermaids"
Some Behavior Traits: Relaxed, Timid.
Duties: Movement of All Water Currents, Conjuration of Rains and Creating a Livable Environment For Life.
What Attracts Them: Shells & Flowers.
On Viewing Elementals: Above it says "Reportedly Seen As:" and then an example of a form they took. They can take these forms and more if they wish. It depends on how they wish to be viewed by you and many times they take the form you expect them to though sometimes they do not.
On Behavior Traits: Above it says "Some Behavior Traits:" and then examples of Behavior Traits. These are general and are there to give you but an idea of what you may expect from them.
On Elemental Duties: Above it says "Some of Their Jobs:" and then examples of the Elemental Duties. What is listed are general duties and do not list ALL the duties by any means. It is there to give you an idea of what their duties entail.
On Elemental Attraction: Above it says "What Attracts Them" and gives examples of what has been used in the past to call or bring them near to either work or converse with them. It is by no means set in stone nor a complete list of things which may attract them. A heartfelt call to them would be enough, but again, it is listed to give you an idea of what has been used in the past to 'attract' elementals.