Don't have any tips for you since I'm not too good at it, don't try and blitz an entire tower the first time around, leave when you feel comfortable to do so because far too many times has my woman starved, also chat to her at length when you visit her each time, don't ignore her.
As for the game itself, i think it gets a raw deal, Operation Rainfall gave us three great games but the likes of Xenoblade and Last Story take the glory and Pandora's Tower just gets shoved aside, indeed it isn't an RPG like everyone was expecting, its more like castlevania but more playable with a genuine heart and an intriguing and well thought out world, the gameplay is ten times as deep as anything castlevania could ever put out too.
Its a pretty impressive game and a one more people should play, like Fragile Dreams: Farewell Ruins of the Moon, Pandora's Tower offers a decent wealth of emotional value which is all too rare in games and is well worth the play on that basis alone.