Every time you get the option to increase your magic, always increase your water element. You will get the best spells. These spells are a necessity to get early in the game.
Easy Boss battles
Before facing Bosses such as Guilty, Begis, or Mammon, collect as many Dragon potions as possible. During the battle with the Boss, use the Magic Barrier spell under Earth magic. Brian will be protected against magic attacks, allowing him to attack the Boss without harm. Use the Dragon potions to restore MP to cast the spell again when it wears off.
Get within striking distance of the staff during combat. Select any spell, then press A. This will result in an attack with both the staff and magic spell in a single turn.
The best Elements, in order, are: Earth, Fire, Water, and Wind.
Entering the Forest
Before entering the forest, fight the enemies around the sign and the trees.
Having all the Elements is still not as powerful in combat as using the staff. When used successfully, the staff almost always does more damage to most enemies than the Elements.
Easy Zelse battle
When facing Zelse in the battle for the Wind Jade, Brian can avoid his second attack by standing six or seven steps away from him. When in this position, Brian will be able to easily outrun his attack.
Avoiding Earth-based magic
Run towards any monster that uses Earth-based magic while they are attacking. They always miss if Brian is close enough to the monster. Since their stone attacks are more powerful then their physical attacks, this strategy will also conserve hit points.
For the best way to raise defense find a monster that uses spells like Windcutter Lv3 or Homing Arrow Lv3. In other words a monster who uses lots of individual attacks in one turn. Defense is accumulated more by how many times your hit, not how great the damage is. Now just simply let this monster attack you, you leave it alone and let it do its thing. While its hacking away at you cast healing spells to keep yourself from dieing. When your health gets too low kill the monster and repeat.
Take Brian to a large area where you can not be attacked by any monsters. Start Brian running in small circles and while running unplug your controller. Brian should still be running in circles. Now if you didn't know, running raises your agility, so just before you go to bed start Brian running in circles, turn off the tv and let him go loose all night!. When you wake up your agility should be super high. If you want it higher, repeat!