Restore HP and MP
While walking around, save your game, and turn off the Game Boy Advance. Load your saved game and all of your character's HP and MP will be restored.
Easy experience
To get a lot of experience early in the game, fight the Snow Dogs that appear in Sub-Vane (the place you go to when you first try to teleport to Vane). The Snow Dogs amount to about 150 experience points and near 1000 silver each. They are very fast and they run away. Equip yourself with items that increase speed. You can also fight their babies, the Snow Pups, encountered beyond the southern gate of Nanza (in the valley where you first meet Tempest). The pups give a little more experience and silver than their parents.
Angel Sword
You can get the Angel Sword (in addition to Guardian's Card) by defeat the Guardian at Protector's Cave. He is found all the way at the end of the cave.
Master Book
Before you sell the Dragon Diamond to Dross at the jewelry shop, keep declining his offer of 20,000 silver. He will eventually call you stubborn and give you a Master Book before he runs off with the diamond.
Protector Cave
After Alex becomes a Dragonmaster, talk to the man behind the counter in Reza at the main building in the north side of the town. He will talk about a cave nearby with a lot of treasure. Exit the town, and you will be able to select that location on the world map. Go there to find a lot of rare items and a hidden Boss. Defeat him to either get the Angel Sword or the Battle Emblem.
Opening red treasure chests
To open red treasure chests, you have to wait until you reach the City Of Thieves and pass the trial to become a member of their guild. When you get the card that lets you open the treasure chests, get all of the red treasure chests immediately. They will make you very powerful at this point in the game.
Red Chest in Ramus's Shop
If you open the chest immediately, you will get a bunny suit. However, If you wait and open it later in the game after you lose to Ghaleon, you will get the Magic Plate. If you wait until you talk to Mia and Kyle after losing to Ghaleon, you will get the Mirror Shield.
Phacia again
After you defeat the real Ghaleon and are in Meribia, try to exit the town. Luna will ask you about why you are still going to adventure. You will walk away from the exit. Phacia appears in front of you. You wil l have a brief discussion with her.
Alex: One hit kills
Make sure that Alex has learned "Flash" (at level 18). You should have it by the time you reach Sub-Vane. If you do not, keep fighting the Snow Dogs in Sub-Vane until you learn it. After you learn it, buy two Quick Boots and equip them on Alex. Next, go to your menu, and then to "Tactics", change Alex's Tactic to "Flash", and everyone else's to "Defend". Enter a battle, select "Tactics", and Alex should wipe out all of the enemies on the field.
Free items
After defeating the magical emperor, go to Ramus' shop. He will let you take whatever desired. You can also get a lot of money this way by selling the items.
Duplicating equipment and unlimited money
This trick allows you to duplicate your equipment. First, equip your characters with the item to be duplicated. You can do this with more than one item. Then, go into a battle and win. Save your game, then remove the item(s) to be duplicated that you equipped on the character. Save the game again. Load your game, and you should now have the item in your inventory (from when you unequipped it) and another one equipped. Repeat this as many times as desired. You can get unlimited money very early in the game by doing this, When you first get Nash, he is equipped with a Sorcerer's Robe. Use this trick to duplicate it, and sell each Sorcerer's Robe for 1,000 silver. When you get the Master Book, use the duplication trick on it. Each sells for 15,000 silver. When you get to Vane, buy the Wind Boots and duplicate them. They sell for 40,000 silver each.
The card traders
You can trade cards with three people in the game. Note: Any other cards can be obtained by killing monsters or buying them from the card lady on Black Rose Street, in Meribia.
The first man is at the Spring near Reza and Iluk, and below the western part of Merryod.
The second Man is in the Spring all the way at the end in Forgotten Forest (east of the eastern part of Merryod; the city with boats everywhere, not the Forest Of Illusion). He only has one card, and trades it only after you have a sufficient number of cards (which should be sometime near the end of the game, probably after the Grindery event).
The last picture is unlocked after killing the final Boss. Go to Ramus' shop and talk to him. It is a picture of Luna.
Glitch: Kyle's "Shining"
Equip Kyle with a glove instead of a sword. When you use his special, "Shining", he will materialize a sword out of nowhere and use it instead of the glove. It will disappear when the special ends.