"Tales of Symphonia" Tips, Hints, and Secrets

Hint #1: When playing as Lloyd, it is a good battle practice to get somewhat close to an enemy, wait for the enemy to hit, jump over it right when it's trying to hit you, then attack it from the back with full force to get unblocked hits. Also, when they turn around and attempt to hit you, employ this method again!

Hint #2: I usually say, in every RPG, when updating equipment in a town, sell all the old stuff either before or after buying the new stuff to get a little money back. But because of the customization of materials in this game, do not ever sell any uneeded weapons/armor/accessories. But if you know every weapon/armor/accessory you DO need, well then, you know what's safe and not safe to sell, so you can do it.

Hint #3: Pressing the Z button in the battle menu allows you to switch characters in the middle of the battle. Great for emergency maneuvers when the AI characters are about to get killed.
Thanks to Kouli for the following Tips/Hints:

Hint #3: To unlock the 'Mania' difficulty, simply beat the game once.

Hint #4: To unlock 'Game Record' at the title, simply beat the game once.

Hint #5: After clearing the game once, load the clear data, then you will be able to buy stuff such as Max HP Increase, Exp*10, Exp*2 with Grade.

Hint #6: To unlock 'Sound Test' at the title, simply beat the game once.

Hint #7: Complete the game once and save when the game prompts you to do so, restart the game using that same file and the game will tell you to insert Disk 1. Upon doing so, you are taken to a screen where you can purchase various options with GRADE that you may have accumualted over the course of the game.

Hint #8: Unlockables
How to Unlock
Carry up to 30 itemsPay 500 GRADE
EXP x 1/2Pay 10 GRADE
EXP x 10Pay 3000 GRADE
EXP x 2Pay 1000 GRADE
Get more bonus EXP from combosPay 50 GRADE
Increase Tension100 Grade
Raise Relationships (Make each character like you more in next playthrough)Pay 100 GRADE
Receive more GRADE after battlePay 100 GRADE
Start the game with 500 more HPPay 250 GRADE
Start with 160 HP at the beginning of a battlePay 10 GRADE
Tranfer over Collecter's Encyclopedia dataPay 10 GRADE
Tranfer over World Map dataPay 10 GRADE
Transfer over all spells/techsPay 1000 GRADE
Transfer over Battle Strategy dataPay 10 GRADE
Transfer over Character Collection (Figurines)Pay 10 GRADE
Transfer over cooking skills (How good the characters are at cooking various meals)Pay 50 GRADE
Transfer over EX Gems (inventory)Pay 600 GRADE
Transfer over EX Skills (equipped)Pay 400 GRADE
Transfer over GaldPay 1000 GRADE
Transfer over Memory GemsPay 20 GRADE
Transfer over Minigame dataPay 10 GRADE
Transfer over Monster Encyclopedia dataPay 10 GRADE
Transfer over play timePay 10 GRADE
Transfer over recipesPay 50 GRADE
Transfer over Relationships (How much each character likes you)Pay 10 GRADE
Transfer over the number of times you used certain spells/techsPay 25 GRADE
Transfer over titlesPay 1000 GRADE

Hint #9: To view all the skits in the game, beat the game, then talk to the mayor of Katz' Village.

Hint #10: After clearing 'Party Advanced Level' in the arena, there will be an Exhibition match with characters from other Tales games, and they are Garr, Farah Oersted and Meredy.

Hint #11: To pull off "Indignation Judgment" twice in one overlimit with Genis, do the following:
Required:
Indignation (Used 50 times)
Spell Charge EX skill
Overlimit Status
Mystic Symbol
Overlimit EX compound skill (Recommended)
First get Genis into overlimit and cast "Indignation"--be sure to "Spell Charge" it. Then, before your overlimit status disappears, cast "Indignation" again, and if you started casting the spell before your overlimit status disappears (This is where the Overlimit EX skill comes in), you will cast "Indignation Judgment." Now go up and physically attack the opponent, and since you have Indignation Judgment already spell charged, you release another "Indignation Judgment."
--Thanks to "Celsius" for the tip/hint/secret