I found this handy Current Moon Phase page. It's a good place to start understanding. Apparently it changes daily, just bookmark it. Tells if the moon is waning or waxing as well, which seems to be important in this venture we have embarked upon. http://www.calculatorcat.com/moon_phases/phasenow.php
Thanks threegardeners, that's useful.
It seems we can alter it for time zone and hemisphere too - very clever. I'd been wondering about that.
I'll see if I can look out an old almanac later to see if we can apply the principles from that - got visitors just now.
brigidlily, here's another way, a reminder using the word DOC. When the moon has the shape of the letter "D", it is waxing. With the shape of the "O", it is full (of course). When it forms a "C", it is waning.