The Phases of the moon can be seen in the image below, and there many excellent websites for learning them. But when using the moon for purposes of setting intent, the phases reveal a whole different picture, the Moon’s energies change depending on the season, its phases and what you would like to accomplish.
But firstly, lets begin with the language of the phases.
Crescent; less than half.
Gibbous; more than half
There are eight parts of the moon’s cycle, starting with the dark moon. (Also known as the new moon.) This is when the moon is barely visible, and each of the moon’s cycles start and finish here.
We begin with the Dark Moon, and onto
The waxing crescent
The first quarter
The waxing gibbous
The Full Moon
The waning gibbous
The last quarter
The waning crescent
and returning to the Dark Moon.
As a rule of thumb, (I feel) a good time to begin an intention is with the dark moon. This allows you to grow your intent, and have it reach fruition with the full moon and complete the cycle as the moon wanes. Naturally there are exceptions to this, and as with all things, trust your intuition to guide you rightly. The same in reverse for letting go of old habits; set your intent on the last night of the full moon, and allow the manifestation to naturally expire as the moon wanes.