Two questions

[Death Match]

I know what to do in your kind of situation. First, as someone already mentioned, move your general up and down, as it draws the bait on the AI. Then, (I am guessing Infantry in middle and cavalry at sides) get your archers to FIRE-AT-WILL. As their general realises this, he will send more troops. He is ANGRY!! Take this chance and bring your archers forward to pour the hell on the main army. (Make sure your archers step out of protection). As the enemy general reaches his limit, he will charge towards your UNPROTECTED archers. Draw them back at the last moment and strike him with your general + many more cavalry. He will die before he has chance to rout. You will suffer 15~20 deaths in your archers, but HEY their general is DEAD!!! From now, you can do what you want but you know that.... ODDS ARE NOW IN YOUR FAVOR!!!!

[Death Match]

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.