Visiting retail stores that carry Pokémon cards, such as Bleecker Trading, is a great way to meet fellow collectors. By building your network, you may find people who can help you access rare cards or link you with people who might want to buy your cards.
Beyond stores, consider attending local Pokémon card tournaments and events. Pokémon cards are interesting because they’re made for use in the Pokémon Trading Card Game. As such, hundreds of people gather to play against each other competitively. These events are great if you want to have a few quick games or if you want to meet people who are willing to buy, sell, or trade cards.