When upgrading, always upgrade the Archers first. The Archer will attack from a distance. First, upgrade Archer Health, then Archer Attack/Power, and finally Archer Speed. When your Archer's abilities are maxed, they will do the most damage and kill enemies with little to no casualties. Then, focus on the abilities of the Spear-Men. After them, strengthen your Swordsmen.

From the start of the game up until the end, the enemy always spreads troops out. If you try this at the beginning of the game, your army will be destroyed. Instead, when selecting units in battle, send the entire army together. They will help each other fight and live through the battles. Always send your army as one large team to obliterate the enemy.