Tactics Ogre: The Knight of Lodis

• Always try to attack from above, and that's including melee; attacks from above and behind do more damage. Elevation also gives bonus range to your ranged attackers.
• Every character has an elemental affinity, they'll always do more damage to the opposing affinity.
• It's a sexist game: women make better mages and men make better fighters. In particular, one of the best magic classes is for women only; similarly, male and female beastmasters work with different creatures.
• Speaking of classes, you might want to check a guide on how to unlock them, some of the requirements are arcane.
• Bring your plot-related characters along with you to battles, they are usually at least solid and sometimes necessary to unlock stuff.