Gone from Count to King, any tips on how to rule?

Been playing this quite obsessively over last few days. racked up 50 hours so far (according to steam).

I've done quite a few playthroughs and I can now easaily go from a count in Ireland to becoming the King of Ireland in one lifetime.

However I am then at a loss on how to play as a King, any advice or tips on how to be a good ruler.

I am aiming to become Emperor of Britannia.