The Moon Cycle
The Moon is always illuminated. But we may not always see it, that is because the time it takes to rotate on its axis is the same as the time it takes to rotate around the Earth. How the Moon appears to us depends on where it is in its orbit around the Earth. If the Earth appears between the Sun and the Moon, in other words, you have in space, the Sun then the Earth then the Moon, then we are able to see the Moon lit up. This is the Full Moon. But if the Moon is between the Sun and the Earth, that is if we have in space, the Sun then the Moon then the Earth, then we won't see it at all. This is a New Moon, which we can see during the day time if one looks closely.
A lunar month takes place as it rotates around the Earth and the time between two full Moons is about 29.53 days on average.
There are 8 phases or cycles. The moon waxes or wanes. It waxes as it is getting larger in the sky, and wanes as it is shrinking. You can also tell if it is waxing or waning by looking at the position of the appearance of the lit part of the Moon. If it is illuminated on the right side then it is waxing; if on the left side, it is waning.
The New Moon
The moon is between the Earth and the Sun. The Sun and the new Moon rise and set at the same time.
The Waxing Crescent Moon
The waxing crescent occurs between the New Moon and the First Quarter. It lasts 6 or 7 days. To view the waxing crescent check it out in the evening.
The First Quarter Moon
The first quarter shows the end of the first fourth of the Moon's cycle.
The Waxing Gibbous Moon
Waxing gibbous occurs between the first quarter and the full Moon, and is also 6 or 7 days long.
The Full Moon
The full moon occurs when the Moon appears on the opposite side of the Earth, away from the the Sun.
The Waning Gibbous Moon
The waning gibbous Moon is a 6 or 7 day period that occurs between the full Moon and the third quarter.
The Third Quarter Moon
On the third quarter, the Moon appears again as a half circle, but it is on the left side rather than the right.
The Waning Crescent Moon
The waning crescent is also a 6 or 7 day period that occurs between the third quarter and the new Moon.
More on Moon Phases can be read at About Moon Phases: Why They Happen and Why We See Them