Eternal Sonata Tricks or Tips?

I just finished the game, killed the last boss, (Not specifying for those who havent beat it)and was about to play encore mode when I realized we would have to level up our characters all over again and I really couldn't be bothered restarting the game... (Probably will in the end but yea...) I was wondering if anyone had some ways to make encore progress a little faster? eg, ways to level up quickly, or something to ease the pain a little?

I started to replay it but never finished. Can't say I know if you can level up faster, but you CAN use the later battle mode levels (or w/e they are called) even from the beginning to make it more interesting. Though "oddly" enough they made it hard as fuck early in the game as well D=