- Generally, the exploring is pretty linear, so you won't worry about missing stuff too much.
- When you get to the lava caves (you'll know when you're in them) there's a missable and kind of hard optional boss.
- Don't use Fredric or Claves more than you need to.
- Don't forget to equip newer skills as they become available. The sub-screen isn't entirely intuitive, so this is easy to forget.
- There's only one character you get in the game who isn't in your endgame party. It's possible to get this character back in a dungeon at the end.
- The battle system gets tighter as you go, so try to get in the habit of making decisions faster than you have to. Each Party Level requires you to play the game faster, so bear that in mind.
- More healing spells are always better. There are times when certain characters will be better healers than others. (At one point, Polka is the best healer in the game, then Frederic, then Viola, and then Polka again, with lots of variation in between.) I would highly recommend against ever going into battle without at least one healer and preferably two.
- Near the end, the bosses are huge difficulty spikes. You will end up grinding like a motherfucker in the endgame.
- The story gradually takes a David Lynch approach to sense making and the ending makes almost no sense at all. Although I try not to get into that stupid Japan/Japanophile stereotyping, there's quite a bit of existential anime angst in the later game.
- The game's New Game+ option cranks the enemy levels way up, so if you're going to do any sidequests or anything optional, do it on your first playthrough.