The new moon occurs when the sun and moon are in conjunction, occupying the same part of the sky from the viewpoint of earth. During this time the moon doesn't reflect the light of the sun, and so cannot be seen (except during a solar eclipse). The moon's un-illuminated side is facing the earth.
The new moon phase is the time of new beginnings - like the Maiden form of the Goddess and the season of Spring. The appearance of the new crescent moon was celebrated as a return of the moon from the dead.
This is a time of growing energy, newness, rejuvenation, growth, renewal and hope. It is a good point to make changes in your life, such as ending bad habits or relationships.