Professor Mason will give you a booster pack after every e-mail he sends you.

When you defeat the Grand Masters, go to the deck machine on the top of the screen before
you get the cards to build a strong deck. If you do not do this, the game will proceed to
the credits and you will have to battle again.

To get the Lv.9 promo Slowpoke easier, put all of your energies except one in temporary
decks. Then, talk to the boy. He will reveal the location for only one energy.

Select the Charmander and Friends deck at the start of the game.

When you have a bad outcome or use a wrong attack in a battle, just turn the system off.
This will save the battle, which you can return to and repeat your turn. This is useful
when you do not want to lose a Pokemon. Simply allow your opponent to attack, then turn
off the Game Boy.

After you defeat the first person, go and defeat him again and to get a booster pack full
of energy cards. You can repeat this trick as needed.

Press B if you do not want to wait for the cards to be done shuffling.

After getting your own deck, go to Sam and offer to play a real duel. You will use the
same practice deck and the flow of the game will be the same as during the tutorial. If
you win, you will get booster pack full of energy.