Sadly you can't do a lot to make the AI put up more of an intelligent fight, except maybe handicap yourself by poking yourself repeatedly in the eye with cocktail sticks until they bleed, and then get someone to chop off your preferred mouse clicking fingers. Eyes watering, and blindness setting in, as well as no fingers to click those all important mouse buttons to order your troops about, and the AI will suddenly become a seriously tough opponent!

To be honest, you'd really need to be a hardcore RTW player to go through that torture, so it's probably best ignoring that advice. You could limit yourself to the General's viewpoint for other ways to make the game a miserable but tougher experience, or never pause the battle. That'll make things slightly trickier for you, although the AI will still probably line up to die in retarded fashion.