Since the moon is central in the timing of God’s feasts, celebrating each new 
month is natural in God’s kingdom. (Is 66:23)
YHWH doesn’t tell us exactly how to do this, but it’s easy for saints to come together under an open sky to worshipfully enjoy each new moon. Like anything else, the more familiar we are with lunar phases the easier this will be.
Monthly worship rhythms keep us aligned with God’s calendar in community, and encourage us to anticipate and prepare for each biblical feast as it approaches, keeping us in touch with God’s prophetic timeline. (Col 2:16)
In inviting us to observe and know the phases of the moon in its relation to the sun, in order to understand the timing of His feasts, it seems to me that YHWH is also inviting us to explore how they work, to ask Him to help us understand and appreciate how He has designed our solar system to behave as it does. In effect, He seems to be calling us to scientific inquiry. This is a natural extension to His command to subdue the earth: “And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.” (Ge 1:28)
It is common for those keeping God’s feasts to start the new month with the visible crescent rather than the new (dark) moon (the lunar conjunction); using the crescent moon has been Jewish tradition for thousands of years. To understand why I think the new moon is a better fit with scripture, please review my discussion of the various viewpoints.