In the opening pages of her iconic work The Spiral Dance, writer Starhawk describes attuning oneself to the natural cycles as such a dance, writing, “The spiral dance was also seen in the sky: in the moon, who monthly dies and is reborn; in the sun, whose waxing light brings summer’s warmth and whose waning brings the chill of winter.” 
The phases of the moon remind us of the eternal cycle of life/death/rebirth, and that similarly, we are always in cycles of expansion and contraction in our lives. With this in mind, I have found new moon and full moon meditations to be a deeply centering practice, and the source of powerful energy for intention-setting.
Though I’m sure I’m not breaking any new ground here, I wanted to share my approach to generally guide me in meditation and tarot divination, and what I understand to be the most broadly accepted approach to working with the energies of the moon.
New Moon – the night of and the day immediately following the New Moon are especially good times set intentions.
Waxing Moon – as the moon grows, reflect on what you too are growing in your psychic “garden”—what needs tending as you move towards the Full Moon?
Full Moon – a period of energetic fruition, this is a good time for divination and any projects that need strong and focused energy.
Waning Moon – moving towards the dark of the New Moon, this is an especially good time to cleanse and release.
Ultimately though I believe what’s most important in any practice is finding what works best for you as an individual!
– Starhawk. The Spiral Dance. San Francisco: Harper & Row, 1979.