Phases Of Moon / Moon Cycles (चंद्र कलाएँ)

Astronomically the revolution of the Moon around the Earth makes the Moon appear as if it is changing shape in the sky. From Earth we see the Moon grow from a thin crescent to a full disk (or full moon) and then shrink back to a thin crescent again before vanishing for a few days. 
The Moon do not have light of its own , it simply reflects light of Sun .While watching from earth Moon appears to change shape because of the different angles from which we see the brighter part of the Moon. This is called Phases of Moon. The phases of the Moon correlate with its angular distance from the Sun. The Moon phases are produced by the alignment of the Moon and the Sun in the sky.
At new moon (अमावस्या), the Moon is lined up between the Earth and the Sun. We see the side of the Moon that is not being lit by the Sun (in other words, we see no Moon at all) 
As the Moon moves eastward away from the Sun in the sky, we see a bit more of the sunlit side of the Moon each night.

 A few days after new moon, we see a thin crescent (हंसिया चांद) in the western evening sky. The crescent Moon waxes, or appears to grow fatter, each night. 
When half of the Moon's disc is illuminated, we call it the first quarter moon (अर्द्ध चंद्र). 
The Moon continues to wax. Once more than half of the disc is illuminated, it has a shape we call gibbous or Kubda Chand (कुबड़ा चांद)
The gibbous moon appears to grow fatter each night until we see the full sunlit face of the Moon. We call this phase the full moon (पूर्णिमा).  It rises almost exactly as the Sunsets and sets just as the Sun rises the next day. 
The Moon has now completed one-half of the lunar months.
During the second half of the lunar month, the Moon grows thinner each night. We call this waning. Its shape is still gibbous at this point, but grows a little thinner each night. As it reaches the three-quarter point in its month, the Moon once again shows us one side of its disc illuminated and the other side in darkness. However, the side that we saw dark at the first quarter phase is now the lit side. As it completes its journey and approaches new moon again, the Moon is a waning crescent.
  

In the figure above, you are looking down on the Earth's North Pole. The Earth spins counterclockwise (in 24 hours), and the Moon orbits counterclockwise (in 27 days). The fraction of the Moon's sunlit hemisphere which we can see from Earth determines the lunar phase at any time. We see a "full," "crescent," or dark ("new") Moon depending on the angle between the Sun and Moon as viewed from Earth. 

Astrologically speaking All lunar phases are divided according to the actual Moon’s position in relation to the Sun and the Earth.
So the Tithis are divided as such: 15 for the waxing phases (or Shukla Paksha) and 15 for the waning phases (or Krishna Paksha).

These 30 Tithis are further divided into three parts  and lorded by three Goddesses, Tri-Devi Shukla  Pratipada to Shukla Dashmi the Moon is ruled by Goddess Durga, Dashmi to Krishna Panchami is ruled by Lakshmi and Krishna Panchami to Amavasya is ruled by Kali

Prasna Marga

Prasna Marga says that if “the Moon is strong it is Durga and when weak the Moon is Bhadrakali, if it is weak and in a Mars sign then the Moon is Chamunda with dark attributes.”

Its a well known fact that the Moon exerts a strong influence on our moods, emotions and perceptions, our minds will be more upbeat and energetic during the brighter, waxing cycle. Starting new projects is recommended at this time.

But During the waning cycle, our minds will be more introverted and prone to self-analysis, meditation and contemplation. At this time, reevaluating our actions and decisions is more favored. And eliminating what is not working any longer in our lives is most supported.
Usually the 10th (Dashmi) and the 11th (Ekadashi) Moon phases are highly auspicious for both worldly and spiritual practices. But the 8th (Ashtami) and the 9th (Navmi) Moon will engender obstacles and sometimes failure.