Wiccans time their magick with the cycles of the moon. When the moon appears to be growing (the period between the new moon and the full moon) it is waxing. When it appears to be shrinking (the period between the full moon and the new moon) it is waning. The days and nights of full moons and new moons are called Esbats. These days tend to be set aside specifically for magical purposes.
Full Moon
Full moon energy is great for banishing unwanted influences in your life. It is a good time to do protective magick and divination. The best full moon magick can be use the three days prior to the full moon, the day of the full moon, and the three days following the full moon.
New Moon
New moon is a good time for personal growth. It is a good time to start a new venture. Its energies are good for healing. If you perform your new moon rituals correctly you should see results my the next full moon.
Waxing Moon
This is a good time for attraction magick.
Waning Moon
This is a good time for banihsment. Banish things like negativity, an addiction, and diseases.