When in battle if you have a poke-ball trainer in your hand use it. If you get heads you can look at the order of they cards inyour deck. Look until you get a stratigy then turn the game off. Click on the continue Duel option at the main screen and you will start of right before you used the Poke-Ball card!
Submitted by Christopher Julian
After you defeat an opponet, when you have to fight a series of people, when the host asks you if you what to change decks say yes and you can save it in the diary. If you lose you can turn the gameboy off, load the game back up and you're able to fight him/her again.
Submitted by Zapping_Dragon