Beat Gaist Easily

Your confrontation with the sole living guardian besides Garr can be made simpler by getting rid of the two torches on either side of ryu. At first it seems that they just replenish 25HP to gaist, but in reality it also makes his fire-based attacks much more deadly.
Note: For a really easy battle, have Ryu equip something like Magma Armor that absorbs Fire-based attacks.

Beat the Dragon Zombie Easily

Battling with the Dragon Zombie after Ryu becomes older is almost always a tough battle because of it's poisoning abilities. To quickly destroy this monster have Ryu cast all his best heal spells on the Creature. This takes care of him in no time. This trick will work on any undead creatures, EXCEPT vampires.
Note: Do not use items! Healing Herbs and Vitamins WILL give HP back to the Zombies.

Beat the Dragon Zombie Easily, Method 2

When you get to the dragon zombie after you grow up just have Garr cast kyrie on him and he will die instantly.

Change Names

In your Faerie Village, put 3 Faeries in a casino. Talk to the one on the left and she'll let you change the names of your party members, including those not with you, and other Faeries.

Control the Kaiser Form

When you choose the Kaiser, most of the time Ryu will be out of control. For better results, choose Infinity + Trance + Radiance as your ONLY genes.

Deis

To get Deis go to Zublo Mountain AFTER you free her. All you have to do is go up the stairs when you enter Zublo Mountain, go up to the slab and press X. She will ask if you would like to be her apprentice. Note: you might have to go back there a few times because she will not apprentice RIGHT after you free her.

Easy Experience

Later in the game, develop the fairy village until you have a copy shop, and copy a Ivory Dice until you have 12. Then use those dice in battle on a enemy (example: the Vulcans in Mt. Zublo). Depending on what enemy you use them on, you'll get 20,000 to 80,000 experience! Using the Ivory Dice in battle increases the amount of experience points you gain in battle.  Using it once doubles the points gain, twice quadruples the points gain, and three times multiplies it by 8.

Easy Ghosts

If you're having trouble beating the ghosts in McNeil Manor, use Heal on them. This even works on the boss.

Find the Wyndian Kids

After Ryu matures, you can apprentice yourself to the kids in Wyndia that you played hide-in-seek with before, but before you can apprentice to them you have to find them in a hide-in-seek game where you have to find them around the world. Here's where to find them: Bais-in B3 of the Dauna Mine Lang-behind a tombstone in the Wyndian cemetery Lee-In the Eastern Wyndian Checkpoint, in a corner behind the guards Wynn-in the lower level of Junk Town on the left side

Free Berries

For free berries go to the coffee shop and kick the tree with apples in it for berries the berries give you 5 hps back.

Get the Beast Spear

As soon as you beat Gaist, you need to search his ashes. You will then get the Beast Spear. This weapon will increase his attack by 150! The only drawback is that it will drain about 9 to 10 HP from him every round.

Get the Ding Frog Fishing Lure

To get the ding frog you have to be a "MASTER OF FISHING++". This is a lure that attracts everything but the guy only gives you 3. You can find him at the cliff just South of Steel Beach.

Get the Royal Sword and the Life Armor

The way to get the Royal Sword and the Life Armor is to fish near Kombinat with the Deep Diver lure until you have 2 Whales, 4 Spearfish and 4 Barandy.(The Barandy fish is at the spot south of the Northern Checkpoint. You'll need a Frog lure for these fish.)After you have managed to get all the fish, return to Kombinat and use a Coin lure to reel in the big, fat thing swimming around. He will ask if you want to buy something. Say yes and the sword and armor is yours! Note that the Life Armor will let you regain a few HP every round.

Master of Agility

To get the fairie Meryleep to become your master, go east of Wyndia where there is a spring that is said to be home of the fairies. Have Peco run and knock a rock into the middle of the pool, and a fairie will appear. She will send you on a mission to get an object stolen from her by a crow. Then go to the mountain west of the Arena, and if you walk behind the mountain a "?" should appear. Enter have Peco hit the tree with the crow on it. Take the object back to the fairie and she will offer to be your master. Your agility will go up +2, but your Hp, Power, and Defense go down -1.

Quick Training Method for Beyd

I found a really quick way to train Beyd for his fight against Zig. I had Momo and Nina in my party. First of all, make sure you have 99 healing herbs(you'll need them!) Be sure to buy Beyd a Moon Sword and a Breastplate so he will have a weapon and armor… you can't train him without them. Remove all armor from all people in your party. This way, Beyd can do more damage to you and his attack power will raise faster. Nina had the assist spells Blunt and Weaken. Cast both spells on Beyd to weaken him so ypou do more damage to him and his HP will rise rapidly. Have your party in the Attack formation with Momo at the front(position 1) Have Nina cast weaken first until it affects Beyd. Have Ryu (and Nina, after Blunt and Weaken have taken effect ONCE)heal Beyd evry round and Momo attack. Have Nina and/or Ryu attack with Momo ONLY if Beyd is fully healed AND dodged Momo's attack the previous round. Using this method, I trained Beyd 8 times. Before the 8th training set of rounds, re-equip all characters. Using this method, I trained Beyd so well, he was kicking MY butt!! Once this is done and the fight between Beyd and Zig begins, Zig was doing 1 HP damage to Beyd and Beyd did about 60-65 HP damage to Zig. Note: Don't have your characters do anything but defend the whole Beyd vs. Zig fight. It will only cause the fight to end earlyer than needed. Good luck!!
OR
With this tip I was able to train Byed in 2 sessions. What you do is unequip everything and equip your weakest weapons or bye weak ones to equip. use for your second slot either Momo or Nina (perferably Momo, because she has "protect") and Peco in your third slot Have Ryu and Momo use "protect" on Beyd then use Peco to attack if peco does no damage then attack with your second weakest charter and keep using "protect".DO NOT KILL BEYD! once his life is lowered enough he will start defending. when he begins to defend attack with Peco.Don't stop using "protect" until all your characters do no damage. attack him for the remaining turns and his defence will rise so much Zig won't even be able to scratch him!

The Magic Master (Mygus)

After you have gone a while through the game, go north of the town of McNeil and you will see a tree stump on the map (a question mark will show.) Enter it and go up and you will see and old man, talk to him. Whichever character that is apprenticed with him will gain more INT and AP, but gain a little less Attack Power and Defense during level-ups.

The Master D'lonzo

Near Windia, there is a coffee shop. Go behind it and there should be a girl walking around. You need 15 different kinds of weapons to get her.

The Master Emitai

After you get older, you can get Emitai as one of your Masters. ( Emitai is the leader of the second team you fight in the Tournament of Champions) After you get older, you go near Ogre Road and there in a path that you go to on your north. There is a hut. Talk to Emitai and he will tell you that if you pay him 10,000 zenny for his mortgage, he will teach you some of his spells.

The Secret Master

After you go to Windia the second time, there is a master. The way to get to him is: See the walls surrounding Windia, there is a pathway beetween the walls (just a tiny incy wincy south), continue to go through this way and you will enter a little house. In this house is a Master.

The Strength Master (Bunyan)

After you get farther in the game, go back to Bunyan's Cabin to make him a master for one of your characters. Any character apprenticed to Bunyan will gain more Attack Power and Defence, and a little less Intellegence and HP when gaining a level.

Thieving

While walking around towns and such you can steal a few zenny's here and there. Give the people a wack with your sword and they will pop out. Usually about 4 to 6 each time. This will even work on dogs and other animals.

Weretiger!?!?! No Problem!!

As you know when Rei rejoins your party he gains the awesome spell WERETIGER. The only problem is he some times attacks your party. Solution... In the begining of the game learn INFLUENCE from a BOSS GOBLIN (Pink Colored). Then after he rejoins have a slower character use it when he morphs.