Alot of people make fake Yu-Gi-Oh cards so that they can make money out of it or trade them for real ones. first of all, look at the little shiny square in the right bottom corner. it should show The Millenium Eye and the words 'Yu-Gi-Oh!'. if it doesn't, it's obviously fake.
Secondly, the writing should be normal not like THIS or like THIS, it should just be like THIS.
Also, some fake cards are leminated and hurt your eyes in the sun.
Alot of fake cards are the wrong colour e.g. Blue Eyes White Dragon with effect...-.-
Some fake cards don't even have the 'Konami' or the 'Yu-Gi-Oh!TM Trading Card Game' on the back.
Some don't have the code on the right hand side. For example: MRD-F000.
If a picture is shiny, it should only be a little shiny, and not so shiny that you can barely see the picture.
Also, sometimes the stars are fake. they should have some kind of shadow on the right hand side as if the sun is coming from the left.
aAlot of fakes have spelling errors, like i've seen before, 'Slifer the Sky Dragin' lol.
Well, that's probably about all there is to indetifying fake cards.