To gain about 1,000 to 2,000 experience points early in the game, once Angelo asks you to check on the Abbot, go to the Ruined Abbey slightly north of there. Instead of flying through the dungeon, walk around until you encounter a Metal
Slime. Metal Slimes will run usually on the first turn, but if not, try hitting it. Metal Slimes have low amount of HP and sometime appear in groups of two. Make sure your main character is equipped with a Boomerang; if you fight two you can hit both of them. Have Yangus attack normally, and do the same with Jessica. Do not use spells, as they have no effect. If you manage to kill the Metal Slime(s), you will be rewarded with about 1,000 to 2,000 experience points, and about 299 to 499 gold. Repeat this as much as desired.

When Angelo asks you to check on the Abbot, go to the Ruined Abbey slightly north of there. Use Angelo's ring to open the entrance underground. Once there, be patient, as at first you will encounter regular enemies. After a few battles you should encounter a Metal Slime(s). They possess only 4 HP but are difficult to defeat because they either dodge or run away immediately. Once you encounter a slime or slimes (up to three), concentrate on only one of them, as it is difficult to kill one. To guarantee a kill, equip a sword with "The Hero", and you must know the ability "Metal Slash." With Yagus, just attack normally. Equip a whip for Jessica and you must know the ability "Twin Dragon Lash," which she will strike twice (and make it very likely to land at least one). It is best to train in the Ruined Abbey after you get Angelo, as he also knows the Metal Slash with a sword like "The Hero." Since the Metal Slime is metal, when you strike it with a Metal Slash technique it is likely to take 2 HP from the 4 HP that the Metal Slime posseses. When Jessica strikes, it is likely she will land at least one hit and take another HP from the Metal Slime. It is not not important if Yagus lands or not, because Angelo's Metal Slash (which can do up to 2 HP damage) will definitely hit. Thus, you have a guaranteed kill, giving you up to 1,000 or more experience points. Also, it is much faster to use Whistle by Yagus to get into battle much quicker, as the slime appears randomly. Additionally, standing in one location is slower; try running around until the slimes do not appear for awhile. When this happens, change locations and use Whistle.

Go to the area before Maella Abbey and run around until you get into a battle with at least one Dingaling. Kill anything besides the Dingaling(s). After only the Dingalings remain, psyche yourself up, heal, or use magic to raise your stats.
Eventually, with a little patience, one of the Dingalings will call for backup. A Jargon will appear. If you are psyched up, use one person to kill the Jargon. Leave the Dingalings alone, and continue to heal, psyche up, or use stat-raising
magic. Do not kill any of the Dingalings. The more of them there are, the better the chance of them calling for backup. Continue to attack only the Jargons and make sure you continue to psyche yourself up. it is important to kill the Jargons
on the first turn, because they can cause heavy damage and blind your party. If more than one Jargon is called, try using Jessica's psyched up attack. It hits an entire group, and should kill any number of Jargons. When you get low on health, or feel that you have killed enough, simply kill the Dingalings; they are relatively weak. Technically, you can get unlimited amounts of experience per battle. However if you get to about Jargon p or Q, you should get about 1,000 experience points. This is very useful for the area. Make sure to equip your characters with lots of medical or strong herbs.

Metal Slimes in the Ruined Abbey (after you acquire Angelo's Templar ring) are worth about 1,300 experience points per kill; They also work rather well later in the game, but only until about level 22 to 25. Also, do not always wait until your
characters are at a few HP/MP unless they have the Evac and Zoom spells. Fight the Dingaling squads who summon Jargons, and only kill the Jargons with Yangus and the Hero from psyching. This will give you some earlier experience than Metal Slimes, and the experience gained is more stable than trying to kill Metal Slimes.