The problem of fakes is getting really bad in the LA area.
I mainly look at the bloated energy symbols, especially the stars on the card - they are such a telltale signs. Look at any card above and you will see that the five points of the star on the colorless energy are well within the circle for a real card but are either shifted or enlarged for the fake ones. :colorless
My daughter got an EyeClops microscope for Christmas and one of the things we looked at was the edge of the real and fake card. Well, I can tell you that both of them are made by gluing two layers (some of the older guides on spotting fakes suggest that the fake ones are a single layer cards).
Another thing that I have seen is the frayed edge. If the fake card has been played or has been handled for any length of time, you will see clear fraying on the edges - little white marks on the edge give it away.
As for color difference in the back, if you put the fake card in a real deck and shuffle it a bit, the fake one stands out like a sore thumb.