If I'm not leader of an army, I try to get ahead of the archers. If you are out numbered, your forces just circle and pretend you will be in the center, instead you can take the archers off to the side and let them fire away at the enemy. If you are the leader and are out numbered. You basically set up a huge wall of dudes and get your archers the ability to fire over the wall. Then as you wipe the enemy, reinforcements on your end are closer to you, while the enemy continues to trickle in. The infantry eventually breaks, the archers stick around but are now vulnerable to your archers and your cav. Cav charge in, let them break the archers and chase stragglers, and recall them. Rinse and repeat this. Meeting the enemy army head on with reinforcements can be hard if you control everyone.