I look for a more faded cinnamon colored head. Some cinnamon colored blushing in the pattern along the back. The more back pattern the better. Lots of alien heads along the sides. The alien heads should begin to connect into one long strip along the tail and usually just behind the head along the neck. The more flames and blushing coming up the sides the better as well but with a good cinny, flames are not really flames like what you'd see on a pastel or fire.. It's more like a high white side that only comes up in places.
You want a cinny that doesn't look like a black pastel. If the head is really black and the back pattern is really black with no cinnamon coloration or blushing at all, I consider it a lower quality cinny.