Fire Emblem/Footsteps of Fate

The Weapon Triangle
Early on in the chapter, you will learn about the Weapon Triangle. Each of three types of weapons, Swords, Lances and Axes, are strong against one type and weak against another. Swords best Axes but fall to Lances. Lances overpower Swords but are weak against Axes. Axes cleave Lances but are bested by Swords. Having a weapon type that is strong against your enemy's weapon type grants you a higher hit and damage rating, but it works the other way around too, so don't go rushing into battle with a weaker weapon.

Terrain
Terrain, the type of ground you are standing on, can greatly affect battle. In this chapter, there are lots of forests around. Whoever is standing in a forest gets a defense and avoid boost during battle. However, going through forests slows down your movement. Think about where to strategically place your units to take advantage of the benefits, but not have those units fall behind the pack.

Normal Mode
The first part of this battle is automatic, but the second part is up to you. Obviously, equip all three of your units with Swords, as every enemy has an Axe. Take down Zugu with Lyn to get her leveled up early, keeping either Kent or Sain nearby to finish him off or rescue her if need be.

Hard Mode
In Hard Mode, Sain doesn't get an Iron Sword, so he will be at a disadvantage. One strategy is to trade Kent's sword to Sain, as Sain has higher strength. Move your units as a group, taking advantage of the forests, and systematically wipe out the enemies. To prevent your weaker units from taking too much damage, let the enemies come to you instead of you to them. Eventually, all that remains will be Zugu. Position Kent and Sain immediately around him and wait. He will attack one and your unit will counterattack. Move that unit away from Zugu and repeat with the other one. If Zugu's HP is low enough (which it should be), finish him off with a swift attack from Lyn so she gains the bulk of the experience.