Circle casting is a process that must be done when doing your spells and rituals, and can be done when meditating. There are various reasons why you should cast a circle. One being for protection from any outside entities or from negative energies. Another is for containing power while you are raising energy for your spells and rituals. Once this power is at its peak, it can then be released. This is called the cone of power and is where the witches hat came into being.

The circle is actually a boundary that keeps everything in and everything out. I also see the circle as a place of altered time, you are literally between worlds when you are inside your circle, it's a time between time.

The circle also signifies the joining of the god and goddess as a whole. Their energies are blending in side your circle, along with the four elements which are earth (north), air (east), fire (south), and water (west), respectfully. All of these put together and with your will of intent, for whatever it is you are casting for, is going to do some very powerful work.

In order to cast your circle you will want to smudge the area with either a smudge sage brush or an incent stick, preferably sandalwood. You will also want to find out which way is north.

At this time it may be a good time to mental prepare yourself for the matter at had. You can do this by taking in a few deep breaths and clearing your mind from all the daily chatters. You may also want to ground and center at this time, some may disagree with this practice, but I see it as a necessary step if you are going to make a strong enough circle hold the energies in. You can't really cast a circle if you are not in the right mood or if your mind is bouncing of the walls, now can you? You have to really use your mind and imagination when casting the circle, you have to focus your will and really concentrate. If your mind is not clear the circle may be weak and the energies may scatter, which can cause whole mess of trouble. I know this first hand at what scattered energies can cause and trust me you don't want to go there!

Once your mind is clear and you fill a bit of energy moving, it is okay to start casting your circle.  Starting at east, or whichever direction your spell/ritual is associated with go ahead and pick up your Athame or your finger which is also fine, mentally see yourself drawing a line of energy. See this as a dim white light that with each go round the light get brighter and more stronger.