Save often to avoid having to redo a dungeon because of a careless mistake against a tough enemy.
Herbal Extract is vital; keep around 100+ on hand at all times.
The Vay Armor is useless when you first get it while the Sword isn't, so use it for a major power boost.
Flee-bags provide plentyof EXP but tend to run away in one round and have 10000 HP, to overcome this, have Lynx or P.J. use Thyxaal on Sandor, then have him attack and do around 8000-12000 damage, then attack with Kinsey to finish it off.
It's recommended to level up enough to buy all the best armor/weapons in a new town right away.
Battles can be easily won with a Malybu/Shock spell by P.J., just make sure her INT is nice and high, give her Staves to boost this, don't ever let her near a bow.
The expensive items in the last town aren't worthi it, so avoid them.
Whips are poor weapons; give Kinsey a sword instead.
Save all Phoenix Hearts and Goddess' Love for the end of the game.