When you get to Serpent's Coil, the enemy there will always be Jells and always appear in numbers of three or more. They are immune to physical attacks. When you are at level 10 or greater, use only elemental Arcanas. After the battle, notice that you will get Arcana Gems exactly according to the Arcana used to kill the Jells. Every battle can result in three or more Arcana Gems. Each gem can be sold it for 100 Gellas. Every enemy you kill using an Arcana is bound to give away Arcana gems.
Gems
In the Fallen Sanctuary, defeat Pilbugs with Arcana to get Earth, Wind, Fire, and Ice gems which can be used in battle, or sold for 100 Gellas.
One-hit kills
As soon as you can, equip the Bunker Cannon II on the Sandcraft. When in battle, always use the force ability "Fire all ammo at once". You should be able to kill all monsters in one hit.
View character portraits
During any non-cinematic dialog, press Select to view a portrait of the character who is talking. Note: The portrait will appear somewhat discolored, as it is meant to have the brown window shading over it. For example, Clive's hair will appear black, and Virginia's hair will look a very deep red).