Castlevania: Circle of The Moon (GBA) Easy level ups

If you wait till she is almost directly above you, Thunderbird seems to hit her more consistently.

Equipment that adds strength will increase the damage of the summon.

When MP gets low, you can switch to INT items and equip Venus and Griffin for the 25% INT for faster MP regen. Alternatively, if playing the game with emulation you can simply increase the speed to quickly gain back your MP.