For a waxing moon the circular arc is on the right hand side and for a waning moon the circular arc is on the left hand side [Here in the Northern Hemisphere].
It would have been nice if the mnemonics Decreasing & Cresting worked but they don't. I personally use Developing & Collapsing to refer, respectively, to the waxing and waning moon. Has anyone a better couple of words than these?
In French we have "premier quartier" and "dernier quartier" for "first quarter" and "last quarter" respectively. The mnemonics work with lower case letters: p and d.
In English, the "d" for "decreasing" also works in lowercase, I guess that you can use "p" for "progressing".
