Pokémon Trading Card Game/Fire Club

The Fire Club members use Fire type Pokémon in their decks, but most members supplement them with Colorless Pokémon as well. All of the Fire type Pokémon are weak to Water Pokémon. The Colorless Pokémon are a mix between those weak to Fighting type and Lightning type. This is probably the best club to start with if you chose the Squirtle & Friends Deck.

John
John is the first of the Club Trainers, and he uses the Anger Deck, which focuses on Fire and Colorless Pokemon cards. Water-type Pokémon Cards and Fighting-type Pokemon cards are recommended for this battle. Watch out for his Double Colorless Energy, since it allows some of his Pokemon to use their strongest attacks immediately. Gust of Wind is also annoying.

Adam
This deck is almost entirely Fire types, so a Water type deck has a major advantage here.

Club Master: Ken
Ken will refuse to face you if you challenge him with fewer than 300 total cards. Note that the count of cards on the Diary screen displays your collection count, not your total count, so is not very useful in this context. If you open the pause menu and select Card, your total amount of cards will appear in the top right corner. Once that is 300 Ken will accept your challenge. You can reach this goal fairly easily just by facing the other members several times and winning, or filling up on Energy cards with duels in ../Mason Laboratory/.

Slowpoke Promo
There is a Lad in the club lounge who will tell you to come back when you have a lot of Energy cards. In reality he waits for you to earn your third master medal. Once you have the medals and speak to him he will ask you for all of your unused energy cards. If you give them to him, he'll tell you about a hidden card in the room that will now be available two tiles to the left of the bookcase. It's the promotional Slowpoke card! Refusing his request will see him run off and you won't be able to get this card until the post-game in the ../Challenge Hall/.

It's a good idea to put all of your Energy cards you can into your other deck slots before talking to this guy. However, if you now find yourself a little low on Energy cards after this, head back to ../Mason Laboratory/ where there are several opportunities to replenish your stock.