Start a new game, and enter "PolkaPolka" as a name to unlock a hidden sound test menu.
Have Mustadio in Chapter 4. After Bervenia, go to the mining town of Gollund. At the tavern, read the "Rash of Thefts" rumor. Go to the merchant city of Dorter. At the tavern, read the "A Call for Guards" rumor. When you leave the city, a battle will start. Win the battle with Balthier's help, and he will join you.
Have Mustadio in Chapter 4. Go to Goug, and read the rumor at Gollund. Go to Lesalia, and invite Beowulf to Gollund. He will join your group after a series of battles.
Have Mustadio in Chapter 4. Successfully complete all ten levels of Midlight's Deep, and The Byblos will join your group.
Have Mustadio in Chapter 4. Go to Goug After Zeltennia. Return Reis to human form, then go back to Goug. Go to Sal Ghidos, win the battle, and Cloud will join your group.
Have Mustadio in Chapter 4. After rescuing Reis from Gollund, return to Goug. Construct 8 will join your party after an intermission sequence.
Have Mustadio in Chapter 4. Accompany Beowulf through Gollund. Reis will be rescued during the final battle in the series.
Have Mustadio in Chapter 4. Read the rumors at Zeltennia, buy a flower in Sal Ghidos, then go to Goug. Go to Nelveska Temple, and win the battle. Reis will turn into human form afterwards.
In Chapter 3, go to the Zekalus Desert after the Orbonne Monastary battles. After the intermission sequence, win the battle, and Luso will join your party.
Keep Lavian and Alicia (Agrias' guards from Chapter 1) in your party in Chapter 4. Land on a City on Cancer I. After the intermission sequence featuring Mustadio giving a birthday gift to Agrias, you will have the Lip-Rouge, which boosts the stats of female characters.
Put an egg on the bottom row of the editing screen. Place the pointer on top, then press Right or Left repeatedly to see a brief glimpse of the face of the monster in the egg.
Reach the indicated job level to unlock the next job in that class:
Archer: Reach level 2 Squire.
Arithmetician: Reach level 5 White Mage, level 5 Black Mage, level 4 Mystic, and level 4 Time Mage.
Bard: Reach level 5 Summoner and level 5 Orator as a male character only.
Black Mage: Reach level 2 Chemist.
Dancer: Reach level 5 Dragoon and level 5 Geomancer as a female character only.
Dark Knight: Become a complete Master Knight and Black Mage, crystallize 20 units, and reach level 8 with Dragoon, Ninja, Goemancer, and Samurai.
Dragoon: Reach level 4 Thief.
Geomancer: Reach level 4 Monk.
Knight: Reach level 2 Squire.
Monk: Reach level 3 Knight.
Mystic: Reach level 3 White Mage.
Ninja: Reach level 5 Thief, level 4 Archer, and level 2 Geomancer.
Onion Knight: Reach level 6 Squire and level 6 Chemist.
Orator: Reach level 3 Mystic.
Samurai: Reach level 5 Monk, level 4 Knight, and level 2 Dragoon.
Summoner: Reach level 3 Time Mage.
Thief: Reach level 3 Archer.
Time Mage: Reach level 3 Black Mage.
White Mage: Reach level 2 Chemist.