Yu-Gi-Oh is a trading card game where two opponents duel against each other with their cards. The popular game can be played at home or you can try out a Yu-Gi-Oh tournament. If you have cards you don't want or need to make some extra money, there are always players looking for better cards. There are several ways you can sell your cards.
Protect your cards by keeping them in card sleeves. This protects your cards from damage and increases their value when you sell them. The closer your cards are to mint condition, the more money you can get for them.
Compare your cards to the deck that was used to win a tournament. If you are at the tournament, then many people will try to recreate the winner's deck. If you have some of the cards that were in the winner's deck, you can sell them at the tournament.
Check the Forbidden List at the Yu-Gi-Oh website. These cards can't be used in a deck at a tournament. If you have cards on this list, they won't be worth much.
Sell your cards in decks. Create decks around a particular character or include special holographic cards in your deck. The more unique your deck, the more likely you are to sell it.
Sort your cards and keep out the rare ones. These are usually worth the most and worth your while to sell them separately. Local card shops may buy these from you, but you may have better luck selling them on an online auction site or a trading card site.
When selling on auction sites, always include pictures of your cards. Buyers want to know exactly what they are getting. Always keep your cards safe in a secure spot.