When you get the elemental Syphlid, leave the Wind Temple and go past where you fought Spring Beak and past the Sprite Village (empty village). As soon as you are back in the forest, immediately turn left and travel until you get near some rocks that are shaped like a diamond. There are about six rocks in all, with four forming a diamond. When you start to get very close, some of the pink rabbits will start hopping towards you. Back up slightly to avoid getting hit and to prevent your uncontrolled characters from hitting them. Since they cannot get to you because of the rocks, immediately start chain-casting spells (cast a spell, wait for the corresponding elemental to appear, then cast another spell as soon as it disappears) Just keep doing this to dramatically raise Undhine, Gnome, and Syphlid. If you run out of magic, just walk back to the right and head for the Wind Temple. The old man there will automatically refill your HP and MP. This trick also works when you get the other elementals. As you raise their levels, it takes longer so it may seem slow when trying to build up to levels 7 and 8. However, by then you should have enough MPs to survive.

To level up your healing magic for the girl faster, just use it all on everyone. Go to Luka, sleep for free, and repeat.