While walking to work in Boston shortly after sunrise you notice that the water level in the bay is exceptionally low. Based on this very low low-tide and the dark cloudless sky last night, the current phase of the moon is a waxing crescent. Among the 8 phases of the Moon, the waxing crescent follows the new-moon phase.
The phases of Moon happen because of the presence of moon's orbit between the Earth and the Sun. The surface of the Moon reflects sunlight and this light reaches the Earth at different angles depending on the location of the Moon in its orbit. This gives us the impression of a waxing and a waning Moon.