Altars are generally set up in the center of the cast Circle for ritual, facing North, which is considered the direction of power, as it is associated with the Earth. Sometimes practitioners prefer the altar to face East, where the Sun and the Moon rise. Either preference is correct. Before casting the Circle be sure everything you need will be inside it.

Sometimes altars are set up specifically for a ritual or magical working, within the cast Circle and then dismantled afterwards. However, many Wiccans and Pagans have altars in their homes that are set up all the time. These personal altars don't need to be as elaborate as what will be described below, and should reflect the personality and character of the practitioner. Altars can also reflect the changing of the seasons with flowers or gourds or spring leaves or whatever your creativity comes up with, depending on the time of year. For special rituals special decorations could also be added, that are also pleasing to the practitioner.

The FOUR DIRECTIONS and their correspondences:

• NORTH Earth: the stabilizing, fertile and nurturing element and is the foundation of the other three (East, South & West).
• EAST Air: home of the intellectual element.
• SOUTH Fire: element of transformation, of passion and change, success, health and strength.
• WEST Water: realm of the emotions, of the psychic mind, love, healing, beauty and emotional spirituality.

There are THREE GENERAL SECTIONS TO THE ALTAR:

The LEFT...

 is for the Goddess and has tools or elements that are sacred to Her. If you don't have or don't want a symbol/statue of Her, a candle that is green, silver or white will do, or seashells, a round stone or corn dolly. A broom may also be laid against the left side of the altar.

The MIDDLE...

 section is for both the Goddess and the God and that is where the Pentacle should rest as well as the Cauldron for magical workings. If it is a large Cauldron, it can be set on the floor in front of the altar.

The RIGHT...

 side is for the God, with the tools that are sacred to Him. If you don't have a figure/statue (or don't want one) to represent the God, a candle that is red, yellow or gold can be used, or pine cones, tapered stones and acorns.

The ALTAR LAYOUT

 Many Wiccans do not use all the formal tools Cunningham gives as the example layout (and even HE says to individualize and do what works for YOU). More closely Nature-based Wiccans sometimes use something much simpler to represent each of the Four Directions, such as feathers for Air, Rocks/Stones for the North, a candle or oil lamp or piece of lava rock to represent Fire for the South, and a bowl of water to represent Water to the West, plus any other artifacts they find meaningful. For example, since I have an animal totem for each of the Four Directions, I personally have an eagle figure to the East, a dog figure to the South, a seal figure and shell to the West, and a wolf figure to the North, to represent my totems on the altar as well. Altars are personal and precious things and nothing is written in concrete that you MUST have. 

My altar one time for the Spring Equinox was a large rock on a little hill along one of my favorite walks along the bay. I picked some wild clover flowers, sprinkled some water and there was my special altar for that day, as I looked out at the sun shining on the water. When I was done, the flowers I returned to the Earth with my thanks and the water evaporated back into the Air to be recycled into rain. I also knew a woman once who had a little altar on a shelf at the head of her bed. It didn't have a Goddess statue or anything, by little stones, pictures of those she loved, bits & pieces of Nature and her travels. Very simple. Very small. Extremely meaningful.

Source: Wicca, A Guide for the Solitary Practitioner by Scott Cunningham.