You want your Leeanne 50CC50 as soon as possible. She's the ones taking the hits for your team. Then level up your Healers as well. Bigger heals can make quite a difference.

After your tank/healer is taken care of, your next most important is dps. If you're losing battles because monsters keep on getting past you then it means your dps isn't dpsing hard enough and you need to level them next.

No Calliope? You want at least two witches for Phalanx 2 to grind for affection + gold/platinum fairies if you need them.

Phalanx 2 has been pretty good in terms of affection item drops.

Both Katie and Phyllis is pretty good. Crave might be dropped cuz he's an attacker and not a UP Generator.

Cypria is strong. Her assassinate probably can save you sometimes.