The people "in the know" around here say that you just need to be targeted with physical attacks.

My sense playing the game was that it actually depended on those attacks missing (which is why at the end I was getting an Agility boost every third battle or so even though they rarely lasted longer than two rounds), meaning you need to dodge them...which you can improve on by raising your evade skill with your equipment. Give everybody a shield and light or no armor (IIRC I didn't use armor until my agility was basically maxed out--you can get away with that if you are obsessive about raising your HP early on--Minwu has a great spell that clobbers your HP without killing you IIRC) or armor that raises evasion (like the thief gloves). And basically just go around like that until your Agility gets really high.