Politics works based on the amount of influence your "family" has, compared to your subjects who arent in your family. I found if you arent going to war immediately when you start its best to put your king as a governor rather than a general, that way he gains influence per turn on a steady stream rather than the small amounts you get in between battles. Also try adopting powerful characters who arent in your family. Essentailly the more power is concentrated in your own hands, the better. Loyalty is similar i believe, with with subjects being less loyal if they have more influence than the king, i may be wrong on that however.

Cheers for that just played around with it then and seem to have got the trick