Renmiri only has part of her advice right--actually, try to get all of your Augments, not just the HP bonuses, first. As you progress in the game, yeah, unlock and learn what magic/weapons/armor that you need, but those Augments, man, will always are active once you active their little squares.

I also recommend trying to have all your characters hightail it to their Quickenings on the License Board; every Quickening gives your characters another Mist Charge, with the second Charge doubling your MP and then your third one tripling your the total of your first Charge.