A = Anthropomorphism
Not my favourite word to spell, I must admit! However, for me, a classic tale will have this as one of its elements. Think Puss in Boots, Shrek, The Chronicles of Narnia etc etc. What matters is the traits shown or speech given to an animal character to have/speak must make sense for the way that character has been portrayed. We see Puss in Boots is a character who would be smarter than his master so the speech given to Puss must reflect that.
B = Beauty
One thing I love about fairytales is that beauty is in the eye of the beholder and is not always the classical definition either. I love the stories of The Ugly Duckling and Beauty and the Beast. Is it just me but I didn't think the Beast was that ugly incidentally (especially as Disney portrayed him? Huge, yes, but that's not the same thing! That aside, there is a strong emphasis that it is a beautiful heart/character that matters most, which I fervently believe. I can't say what single thing makes me love fairytales but this is a very high contender for being the top one.
C = Characters
There isn't one dull character in fairytales, is there, when you come to think about it. There shouldn't be in your stories either. (And even when a character is meant to be "dull", there still has to be something about them that will make your reader want to find out if they stay that way or change or if there is a point to the dullness. Maybe the lead character needs a duller one's sensible comments to point them in the right direction?).
More next time....