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.
Easy wins
After you get the Devil's Tear, give it to Jess. In every fight, she will use Smite and kill enemies. On top of that, have everyone else attack so that they can increase their special move gauge.
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.
Devil Tear
Go to Lann after becoming a Dragon Master and talk to the chief of the village. When he asks if you should celebrate, answer "Yes". After the celebration, he will give the Devil Tear to you. The Devil Tear gives you a full special bar at the beginning of every battle.
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.
Rare Dragon Cards
Once you return to Saith with Ghaleon in your party, talk to a man in town who will tell you about an old hag in the forest who collects cards. Visit her. Then, after Ghaleon captures Quark, go to her and she will give you the Quark Card. For every dragon you meet after that, visit her to get their Card.
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.
Secret sewers
You can go to the sewers in Meribia after the Grindary event. The sewers are in the building that was previously guarded by the two men at the harbor. You can get the Card D Grave Card in the sewers. It is in the last place in the sewers, partially hidden at the bottom of the screen.
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: Liner attack
When you get the Angel Sword (in Protector's Cave) and Master Book, equip both of them on Alex to get his most powerful special attack, Liner. It does massive damage to one enemy.
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.
Stronger skills
Equip your character with Quickboots (the ones you can buy in Vane for 80,000 silver). If you equip the character with two Quickboots, his skills should be two to four times stronger than before, in addition to increasing you NOA by four. You can easily do 999 damage this way. Note: this only works on Alex and Kyle, since they are the only ones that can do physical damage with their skills, It also works with Jessica's Crimson (her second special attack).
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 third man is in Meribia, near the ship dock. You can only trade with him after the Grindery event.
Secret gallery pictures
There are three secret pictures you can unlock and view in the gallery.
Go to Althena's Shrine after you get Kyle. Talk to the woman on the right. It is a picture of Jessica.
After you lose Nash and get the engine for the ship, go to Iluk and talk to the man in the top right house. It is a picture of Mai.
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.