Waxing moon
The traditional choice, especially the days just before full. Growth, increase and abundance.
Currently Waxing Crescent
Lunar calendar for weddings
The Moon is waxing right now. The traditional choice, especially the days just before full. Growth, increase and abundance.
Waning moon
Traditionally avoided, on the reasoning that a marriage begun on a shrinking Moon shrinks with it.
Does it work?
Widely observed across European folk custom, and echoed in the Hindu and Chinese calendars, which pick dates by lunar reckoning for the same reason.