I brand this on all my boxes and use push pins to track what I did last time I was here:
When doing an inspection I use the day of the month for today, for the numbers, and whatever I think is relevant otherwise. The abbreviations are: Egg=Eggs, Opn=Open brood, Cpd=Capped brood, Fsg=Festooning bees, Mkd=Marked queen, Gnt=Gentle bees, Def=Defensive bees, XQ=Queenless, VQ=Virgin queen, LQ=Laying queen, Gft=Grafted cell, Swm=Swarm cell, Spr=Supersedure cell, Emg=Emergency cell, Dx=Disease, ^=on the increase v=On the decrease, Flp=Followup (i.e. they need something, food, bees, more supers etc.)
When doing queen rearing the date can be used however you think will help. For instance you could use it for the day you expect this queen to be laying or you could have it be the day you put the cell in (which is easier to keep track of) and then the day you saw it emerged and then the day you saw the virgin queen etc.
Sometimes I use multiple colors. i.e. if I SAW the virgin queen I use a purple pin. But if I have evidence to suspect a virgin queen I use blue. If I introduced a virgin queen rather than letting her emerge, I use red. If I saw evidence of a laying queen but didn't see the queen, again, I use blue. If I saw her I use purple. I like to use Red for Flp because I need to do something or that wouldn't be marked and red gets my attention better. Also I like red for XQ because if they are queenless something needs to happen. So it's best if I DON'T use Purple or Red elsewhere so I can easily see which mating nucs or hives need a queen or a queen cell and which ones need some kind of followup.