I have several different styles/colors of tanks and drippers. That and colored drip tips helps a lot. I also have a tendency of leaving the current rotation bottles on my coffee table. Don't know if you're a girl or would have any issue with this, but some people make like charms to hang from their tank that represents the flavor. (Ice cream cone for vanilla, cupcake for cupcake, fruits for that fruit, you get the idea.)
So like right now for instance, I know that the PT2 with blue drip tip is Winter's Bite, the mini PT2 with black tip is Black Honey Tobacco, the mini PT2 with silver tip is Cafe Mocha with Sweet Complexity, the mini RDA is Sweet Complexity, the RSST is Castle Long, and the Crown is Queenside.
I have a couple more filled tanks that aren't in current rotation so I would have to taste them to be sure, but I think I remember what they are anyways. It's all about finding a system that works for you.
Good luck!