Personally I ignore all missile units and concentrate all my missile fire on melee/cav units. The reason is when a melee starts, I re-aim my missile units to attack their missile units, and the only ones that give any stress to inflict casualties on is pavise units. These I will attempt to attack via flanking with light cav or an expendable unit like urban milita.

Found the AI tends to fire into melees quite often, inflicting casualties on both side.

As for CK's, high morale spearmen or or better pikemen with high armour upgrades on hold position do quite nicely while you flank with a bonus vs armour unit like gallowglasses.

And cannons! Must have cannons! Great for blasting through rows and rows of knights. Want to kill their general right from the start? Blast him with a cannon.