Instructions
Look at the back of the card. The blue strip that runs around the border may not be printed as crisp and blue if the card is a fake. However, if you do not have a real card to compare it to, this is a judgment call that may not be accurate. Aged cards may look a little less sharp around the edges, so be careful about using this sign as your only way to find a fake.
Check the front of the card. At the top, you will see the word "Pokémon" with an accent over the "e" (it should look like "é"). If you do not see this accent mark, the card is fake.
Check the energy symbol on the card. These are the symbols that appear at the top right and lower left of the card describing the amount of energy or power a character has. They are shaped as a sphere with a tiny symbol inside. Most counterfeit cards have energy symbols that do not give enough of the sphere around the symbol, and they make the symbol too large. If it is difficult to see the sphere on your card, it is probably counterfeit.
Check your holographic cards. A fake holographic card may appear to be a real card, but when you move it, the image will not change. The background will also seem a little distorted because when the image was scanned to create the fake, the real one (being holographic) will make the scan look slightly blurred and noisy (with a lot of strange specks).