I'm ....-retentive.

I use a Brother label-maker 1/4" or 3/8" width, to make labels that fit around the battery end of cartomizer and 510 carts nicely. Short name of the liquid and its nic strength. So "ChocoMnt 24", etc. They are vinyl so sturdy, and they pull off easily when you need to take them off. Since they are skinny, they look a bit like a normal band on a cig or something.
Then in my 'tackle' box I have slots labeled for Blank, Refill, 0-10, 11-18, 20-26, 30-36, and 48. I put the ones that need refilling into the refill slot when done. When I fill them I put them in the right strength slot, so I can grab an appropriate strength and just pick a flavor.