The Altar can be done several ways. Imagine a table...rectangular in shape...draped with a black cloth. In the center to the back of the altar is a candle of white. This is for purity and protection. I never do a ritual without a white candle burning on the altar. Many groups use this for the North candle as well if space doesn't permit to have the watchtower candles in the floor etc. In the right hand corner is the God candle...in a color fitting...sun or forest colors of gold, orange, green etc. In the left hand corner is the Goddess candle, in sea colors or earth, or birthing colors...silver, red, green, purple etc. This is not traditional...in Gardnerian trad the Goddess goes on the right and the God on the left..but I feel since the Goddess rules the left brain and the God the right it should be this way...this is a bit of eclecticism coming out in me *G* But it can be done as you see fit. Your altar is for you and those you do circle with...so it should suit you as much as it can.
God and Goddess symbols can also be place, on the same side as the candle...some dont use symbols...if room permits we do both. For the Goddess it would be fresh flowers, willow branches, holey stones, shells, moonstones to name a few. For the God it would be fresh flowers phallic stones, antlers, pine cones, oak leaves and sunstones.
The censer is placed in the middle, in front of the altar candle, in a heat proof container filled with sand or salt. You can use loose incense on charcoal briquettes, stick or cone incense or a smudge stick. Use according to purpose, mood etc. NEVER LEAVE CANDLES OR INCENSE BURNING UNATTENDED AND USE INCENSE IN A WELL VENTILATED AREA!!!!!
The salt and water bowls, water on right salt on left of the altar, in front of the censer. These are used to in essence creat holy water...the attendants and the circle are blessed and asperged with the combined water.
The pentacle is set in the front of the altar lined up with the censer.
Any tool (ie athame, wand etc) are set to the right side of the altar.
The chalice is set to the left of the altar, and the bowl of cakes is normally in the floor in front or under it...unless there is enough room and it is then set to the right beside the tools. The sword is also placed in the floor in front of the altar.
Various other items are placed as you desire, ie stones, other tools, jewelery, etc. Some wish for the Book of Shadows to be on the altar, but we memorize everything, so we dont normally keep it there. Other things like extra incense, charcoal, BOS anything you need for a spell, extra wine, music makers, all this may go under the altar, room permitting.
The ideal altar is an old dresser without the mirror...then you can keep your supplies in the drawers and not have to worry about the space issue.
The altar cloth can be color specific for the Sabbat or the magickal purpose. All purpose is black, for the cloak of night and power. Some opt for no cloth at all. Depending of the altar type, (ie how it looks). Altars should be censed and dedicated for their purpose even if it coubles as a coffee table, dresser etc at other times. BUT if at all possible use your altar only for an altoar. NEVER put things on it that do not belong, (ie cans plates clothes) This will preserve the purity of a permanant altar and you are showing your respect for your sacred space. It retains energy you expose it to.
People who cant practice feely for whatever reason can keep an altar as well. Many altars can be found in the top drawer of a dresser etc. Natural altars are found everywhere. When you are going out to do ritual it isn't always necessary to take one...just look for a good flat rock, grassy spot or tree stump. These work wonderfully and are a gift from the Gods. Any witch who has lugged tables and bags or ritual items a few miles to the perfect spot and later decided to go 'au natural' has seen that is is always provided! Not to mention the great relief of NOT having to carry all of the heavy trappings!