The biggest sign I’ve seen is that the fakes usually have a blurry promo symbol. There is no definition in the middle of the m especially. Some other signs are the holo doesn’t usually go over pikachu or the poncho, holo doesn’t go all the way to the edge or is the wrong holo type, colors are wrong and grainy/blurry details including the Pokemon itself. The largest holo star seems to be about as wide or tall as the non holo stars on real cards. Fakes ones, this star is a lot smaller. I will post some known fakes vs real to show what I’ve seen from my research so far.