I found this helpful too, though I'm a Ranger. I find that the most difficult enemies are those Sinows. They move fast, they do high damage, they charge if I get far away, and the orange ones even self-heal. It's like they're designed to eat RAcasts. =(
I hadn't realized that going to the Hospital refreshes my supply of Traps, either. I just thought I had a set amount per game.
Even better, it's only like 10 meseta for a refill! I love the Hospital now. My feeling is that Confuse traps are the best traps. If I'm up against two Sinows rather than just one, dropping a Confuse and then beating them both with a Cannon (thanks, Asylum!) ends things quickly and painlessly. If I drop a freeze trap, they're free again by the time I get range; even better, with Confuse they've damaged themselves pretty badly.
Any tips for Vol Opt, beyond what's in the guides? I'm still annoyed that I can't use traps in boss battles. Hardly fair, is it? I mean, RAmars can still cast spells.