1. Identify the exact card
Use the card name, set number, rarity, language, and finish. A reverse holo, illustration rare, secret rare, promo, and normal version can all have very different prices.
2. Check condition
Look at corners, edges, surface scratches, dents, bends, and whitening. Condition can change the price more than the card name does.
3. Compare current market prices
Use the live Pokemon tracker to check current market snapshots, then compare recent sold listings for the exact version and condition.
4. Avoid pricing traps
Do not use the highest active listing as your price. Asking price is not the same as market value. Recent sold prices and current market snapshots are better signals.