The Moon is the embodiment of the Goddess and is also an important source of natural energy that is essential in magic. The lunar phase is important in determining the best time for magic.
There are basically two lunar phases: waxing moon (ideal time for positive magic – work should be concentrated on drawing what we want towards us) and waning moon (ideal time for banishing/negative magic, study, and meditation – work should be focused primarily towards banishing/rejecting what we want out of our lives).
In between you have the dark moon (the time of greatest power for banishing, negative magic and meditation as well as a time to look within) and the full moon (the time of greatest power for positive magic). During an eclipse, any type of magic worked or energy sent out will be amplified.