When you start a new game I suggest to keep on practicing in the simulation machine. Make sure to buy all the spells, the best armor, and the best weapons in the town before you leave. And whatever you do, never eat meat or install parts after a battle! Turning one of your members into a monster or a robot makes them weaker and replaces their magic with monster/robot abilities. Having the most expensive armor and weapons you can buy at any moment is the best thing to do if you want your battles with "end bosses" to be quick, because they have loads of HP! So to do that you're going to be spending quite a bit of time running around collecting GP. The best spell in the game is Stone. It automatically kills an enemy, and gives you experience for it too. Exit and Exit 2 automatically kill the enemy as well, but it doesn't give you any experience. The strongest spell in the game is Flare, which can be obtained by combining two fire stones.