The cone of power is created by a generation of energy within a circle. The energy expands into the form of a cone, the base of which runs the diameter of the magic circle. The cone of power can then be directed toward a specific magical goal. Any excess energy is then grounded and returned back to the earth.
The energy for this is raised my dancing, chanting, etc. It can be done by a group or by a solitary practitioner. If there are three of you, you could try dancing around the circle while saying a chant associated with your goal. As you do so, try to visualize the energy you are raising forming into a cone. When you feel that you can raise no more energy, focus on releasing the energy toward your goal.
" The Witch Book: The Encyclopedia of Witchcraft, Wicca, and Neo-Paganism " ~ Raymond Buckland.