If my above tactic does not work, (it always works with me) make sure you have a STRONG middle infantry. Then, you can be assured that they will hold firm and engage in a length fight while you cavalry charge behind the enemy flanks and kill the enemy. It kills more and it is more effective. As it is quick, (cavalry are very quick at flanking attack) You have more army to focus on the enemy general who at times are overpowered and the toughest of units.