For my army compositions, I usually have at least half of my army made up of cavalry and the rest as infantry with a little missle support. I target the enemy cavalry first, wiping them out quickly with a mass charge of 4+ units of cavalry destroying there mobility. The rest of the battle is easy and I would engage the enemy infantry with mine and then charge my cavalry into the enemie's back causing mass rout. This works wonders against factions like turks, russians, or byzantines where there is a large focus of horse archers since they start off far away from the main battle line loowing you to wipe them off without being afraid of enemy infantry getting into the mix