Think of the Kikos by their body colors: Blue, Green, Grey, Peach (or Orange, whichever you prefer, but I don’t use that because it’s not as snappy and short as Peach), Pink, Red, Teal, Yellow. There are two multi-colored Kikos: the one that is sort of white-faced and red-bodied I call “Cute” and the other who is yellowish with a funky plaid-like pattern I call “Ugly.”
The Kikos start out on blue backgrounds. However, as the levels progress, they’re on other shades, too. When you reach that point in the game, start referring to each Kiko as its body color and background color. For example, I call a blue guy on a yellow background “BlueonYellow” as opposed to his friend, the blue guy on the standard blue background, who–after level 4 or so, when the other background colors start to show up–I call “BlueonBlue.”
Depending on how eidetic your memory is and how well you play, sometime after level 7 (I usually start doing this on level 9), you may want to click the top-left Kiko and just begin rapid-fire clicking across each row (when you hit a wall, go down one and back across the other way) until you find the mate to _that_ Kiko. As you click around, keep repeating the body+background of the Kiko you’re looking for: BlueonGreen BlueonGreen BlueonGree… Aha, Got it! Along the way, you will almost certainly clear matches that were situated next to or very close to each other. After you find the mate to the top-left Kiko, move to the next Kiko over and start rapid-firing again.
You can also try clicking the first _two_ Kikos and rapid-firing across the board until you find each of their mates. Repeat each of their body+backgrounds as you go: TealonYellow PeachonRed TealonYellow PeachonRed TealonYellow PeachonRed… Then, once you’ve found the mates to both of them, go back to the top and start again with the next two. – TV Diva