There is a possibility your character's level is not high enough. Try the following to build up your character's strength:
- Earn EXP by completing the dungeons and raise your level.
- Use equipment with high stats.
- Strengthen your items with the Level Up Items feature.
If you try all that and are still finding it too hard, try the following:
- Equip items that are strong against the enemy's elemental weakness.
- Use tool bags containing tools such as spears and restorative items.
- Set high-level skills.
- Add strong buffs to your items with the Item Remodeling feature.
- Use the Organize Party feature and take some minions with you.
- Team up with strong friends.