Prepare the room you will be using by thoroughly cleaning it first, and then going around the room with your censure lit with protection incense, or with a smudging wand 

Of course, if you are casting your circle outside, you do not need to worry about cleaning. 

Generally, the size of my circle is about 9 feet in diameter. The size can be changed as needed. (You may not have enough room, etc). 

Place your 4 corner candles around the circumference of the circle. One candle to mark the East, one for the South, one for the West, and one for the North. 
You may need a compass to orient yourself with North. If you do not have a compass, simply notice where the sun comes up (in the East) or sets (West) and you can figure out the Quarters from there. 

Set up your Altar so that everything you need is within easy reach. 

Sit in front of your Altar facing East. 
Meditate for a moment to relax and prepare yourself for your ritual. 

While you are doing this brief meditation, envision yourself surrounded by a protecting ball of light. 
Build this vision mentally until you feel ready. 

Ring the Altar bell three times and stand. 
Light your Altar candle, and then move to the East with your lit Altar candle. 

Say: 
"Here in the East I bring in Light and Air. This is to illuminate my temple and bring it the breath of life." 

Light the East candle from the Altar candle, and move on to the South. 

Say: 
"Here in the South I bring in Light and Fire to illuminate my temple and bring it warmth." 

Light the South candle from the Altar candle, and move on to the West. 

Say: 
"Here in the West I bring in Light and Water to illuminate my temple and wash it clean." 

Light the West candle from the Altar candle, and move on to the North. 

Say: 
"Here in the North I bring in Light and Earth to illuminate my temple and bring it strength." 

Light the North candle from the Altar candle, and return to the Altar. 

Replace the Altar candle and pick up your Wand or Athame (whichever you use to raise power). Move to the East corner. Point your wand or athame down so that you "see" the edge of the circle off of the point of the tool. 

Concentrate all of your energies down through your arm into the tool. Let the energy be released out of the tip and move around the circle deosil "drawing" the circumference or the circle with the energy flowing from the tool. 

Go completely around the circle, finishing in the East before returning to the Altar. 

Stand again in front of the Altar, hold your wand or athame in your right hand, and the Altar bell in your left. Ring the bell three times, and replace it on the altar. 

Put the tip of your wand or athame into the dish of salt and say: 
"As salt is life, let it purify me in all ways that I may use it. Let is cleanse my body and spirit as I use it in this rite dedicated to the Goddess" 

Take three pinches of the salt from the dish and drop them one at a time into the dish of water. Stir the water deosil with your wand or athame and say: 
"Let this sacred salt drive out any impurities in this water so they may be used together in the service of the Goddess - throughout these rites, and at any time and any way I choose to use them." 

Take the bowl of salt water, begin in the East, and sprinkle the water around the circle, finishing again in the East. 

Return the bowl of salt water to the Altar. Pick up your censure, and go around the circle beginning in the East and ending in the East, drawing your circle with the smoke. 

Return your censure to the Altar. Dip your finger in the water and mark a cross with a circle around it over your third eye. 

Dip your finger again in the salted water, and draw a pentagram over your heart. 

Say: 
"I consecrate myself in the name of the Goddess, bidding her welcome to my temple." 

Move again to the East with your wand or athame. Draw a pentagram in the air over the East candle while letting your energy flow down your arm into the tool. 

Say: 
"Angel of Air, I do summon you to witness this rite and guard this circle. Powers of air, protect me as I journey between worlds." 

Move to the South. Draw a pentagram in the air over the South candle while letting your energy flow down your arm into the tool. 

Say: 
"Angel of Fire, I do summon you to witness this rite and guard this circle. Powers of fire, protect me as I journey between worlds." 

Move to the West. Draw a pentagram in the air over the West candle while letting your energy flow down your arm into the tool. 

Say: 
"Angel of Water, I do summon you to witness this rite and guard this circle. Powers of water, protect me as I journey between worlds." 

Move to the North. Draw a pentagram in the air over the North candle while letting your energy flow down your arm into the tool. 

Say: 
"Angel of Earth, I do summon you to witness this rite and guard this circle. Powers of earth, protect me as I journey between worlds." 

Return to the altar, and raise your wand or athame up high while saying: 
"I hail the four corners and the Goddess. I invite the Lady and welcome her to witness this rite I hold in her honor." 

Continue to hold your told up high and say: 
"This circle is now cast and I am between worlds. I am beyond the bounds of time, where night and day, birth and death, joy and sorrow meet as one" 

It is never recommended to leave the circle (even with opening a doorway first) during magickal work.