Weapon size is important. Attacks have a limited area of effect, making it possible to miss if you are too far away from your target. Remain close to your opponent and take advantage of your long weapons or attack range if available. During the campaign, not all your fighters must be kept at full health. Consider sacrificing some of them to make it easier for your better heroes to take out more difficult enemies. When a character dies during battle, all the damage they inflicted will still be there, allowing their replacement to continue where they left off.