The element we are going to call is Fire, in the South. At noon, the Sun is as far south as it will go in the course of any given day, and it is also at its most intense heat. This seems as likely a reason as any to associate south with Fire.
Fire is heat and passion. Fire is untamed. It can be gentle, as it is with the warming flames of the hearth, or it can be the uncontained destruction of a raging wildfire. Fire is an odd element, just because of its material properties.
The main color associated with this element is red, which shouldn't be a complete surprise. In order to call Fire energy into our circle, we call the Guardians of Fire. Some call the Guardians of the Watchtowers of Fire or South instead. These Guardians are the embodiment of the Elemental energy.
Take a minute to think about Fire. What do you associate with the element? What form do you think a Guardian of Fire might take? This one is a bit trickier than other elements, as there are few creatures that we immediately associate with fire. Take, for example, a salamander. She is curled upon herself in lazy eights, an orange curlicue that would easily find camouflage among tongues of lava. Something that is sort of a cross between a dragon and a gecko, no wings, but large, with slick-looking scales.
There is actually an animal called a Fire Salamander. Salamanders tend to be a traditional association with Fire. Fire may feel feminine because it has the power to create as well as destroy, and life is created through the female.
Certain plants and seeds, like pine cones, can only fully sprout when touched by fire (it will open the pine cone, releasing the seeds). If placing Fire to the South doesn't ring true for you, feel free to change it with good reason. If you live just east of a desert, for example, then it might be more appropriate for you to put Fire in the East!
Even if you do decide to use the traditional correspondences, take some time to really think about why you associate the Element with the direction. It is more important to make a personal connection to these Elements and your magic than to just follow directions or anything written in a book.
After you have decided in which direction you will place Fire, make a list of all the correspondences you have with both the direction and the Element. You will probably notice some themes running through your list. Once you have done that, take time to meditate on the qualities you have discovered, and ask to meet the Elemental Guardians.
They might look quite different to each person. Maybe your Fire Guardian will be a Phoenix, like Fawkes in the Harry Potter books. Or a dragon. When you cast circle again, and call the Element of Fire, visualize your Guardian being present at the circle. Tap into the energy available there. Feel the heat warm your face.
Calling Quarters is not just saying some poetic verse and lighting a candle. Calling Quarters is meant to bring the energies of the universe to your sacred space. Your circle and your magic, will be stronger for it.