The most common way to organize Pokemon cards is by set. To identify the set, look for a little symbol at the bottom of the card, next to the card number.

Each set has a unique logo printed on the card and a unique list of cards. To determine the set, you locate the logo on the card. It's right above the lower border of the card. Below is an image showing the logo on a card. Then look up the logo in a list of Pokemon set symbols. The only set that does not have a logo is the Pokemon Base Set.

Each Pokémon card is associated with a set. Sets are released typically four times a year, and all the cards in a set will have the same symbol identifying the set. You can see all of the Pokémon Sets and their symbols here: Pokémon Sets For the older cards, the set symbol is on the right half of the card, just below the Pokémon picture.