Some other pointers for more stars: try to chose tough fights - if you hold off a three-to-one attack by an enemy there's a strong chance of getting a "skilled defender" and "skilled last stand" virtues, both of which earn you an extra star each (on defence); attacking a superior force can get you "skilled attacker", as can a series of successful attacks. Try grooming one general specifically for attacking, and he'll get attacking virtues.

I think command stars come in a geometric progression: after 1, 2, 4, 8, 16 wins etc, so to get to the higher levels takes a LOT of battles, so it really does help to earn some virtues.

And yeah, "good runner" vices really suck -- once you've got that you may as well retire the general, even if he has a lot of stars. I'd prefer a low valour/high morale army over a high valour/low morale one any day.