How Do I Cast a Circle?
How do I cast a circle? What am I supposed to say? Am I doing this right? Why am I doing this again?
The truth is, there are countless different ways to cast a Circle. Your Circle is like a portable "church" - your own sacred space. It is cast to keep out negative energy and to keep your magick and the energy you raise all in one spot. If you think you're doing it right, you probably are. It may be a little while before you feel comfortable doing it, but keep practicing!
The "right words" are the ones that come from your heart. They are going to depend on why you are casting a Circle. The words you use when you are doing a ritual to celebrate Beltane are going to be very different from the ones you use to mourn the passing of a loved one.
Many people use a symbol of the element they are calling at each quarter.
For Air in the East, you could use incense, a feather, or a yellow candle.
South is fire. You might use a candle, dragon's blood resin, or if you are outside, you might have a bonfire here.
For Water in the West, you could use a blue candle, a cauldron or goblet filled with water, or your chosen vessel for holy water.
North is Earth. You might have a small dish of earth, a brown candle (some people prefer green), a pentacle, or a plant.

Here are two examples of what one might say when casting a Circle. The first is my own, one I might use if casting a Circle on Esbat, working magick for a new job. In this example, I have candles at each quarter.
East, Air! Come, be with me in my Circle tonight! Guard and protect me as I celebate Esbat. Bring your gifts of open communication and quick results! Thank you Air. Welcome, and Blessed Be! (light candle)
South, Fire! Come, be with me in my Circle tonight! Guard and protect me as I celebate Esbat. Bring your gifts of transformation and rebirth, energy and passion! Thank you Fire. Welcome, and Blessed Be! (light candle)
West, Water! Come, be with me in my Circle tonight! Guard and protect me as I celebate Esbat. Help to cleanse and nurture me and I continue my search for a new job. Thank you Water. Welcome, and Blessed Be! (light candle)
North, Earth! Come, be with me in my Circle tonight! Guard and protect me as I celebate Esbat. May your strength and stability aid me as I search for a new job, and keep me focused on my goal. Welcome, and Blessed Be! (light candle)
See, that didn't hurt, did it?
Here is an example I found online quite awhile ago. A source was not given to me. This is more poetic and is not ritual specific.
(Facing East):
Air, Wind, breath and blow. Dawn light breezes go. (Repeat 2x)
I am the breath, I am the breath ,
I am the breath of the Goddess.
(Facing South):
Fire, Fire, warm desire. Charge me, form me, 'til I'm higher! (Repeat 2x)
I am the heat, I am the heat
I am the heat of the Goddess
(Facing West):
Water falling, rain and snow, water rushing like a stream (Repeat 2x)
I am the tears, I am the tears,
I am the tears of the Goddess.
(Facing North):
Earth, Mother, come to me. Heal my wounds and comfort me
(Repeat 2x)
I am the Earth, I am the Earth,
I am the form of the Goddess
(Walk circle three times, chanting):
Air, Fire, Water, Earth
Book of Shadows