Accumen is King

Gold buys armies, armies that win battles gain influence. Even faster with Muslims, send 9 Jihads at one provence, win and gain 9 influence... very cheesy.

Influence is an easy one to gain.

Kings do not live long compared with generals. So I rather concentrate beefing up my generals who last several generations of Kings. Typically these are ex-princes as they have good starting Stats as do some of the neutral starting generals... El Cid is around for a long time in the game.