You do have a lot more ability to influence the game than you think. It just takes a lot of practice until you realise that. Marrying yourself to a powerful family is a must as a small dynasty. The first games are the best though. My first game I started as the Duke of Salerno, did nothing for a hundred years before I ended up marrying the female Basilissa of the Byzantine Empire. Inherited it when my character and his wife died before totally fucking it up, losing three quarters of it in independence revolts before being ousted and ruling half of the empires remaining lands as the Despot of Syria. Was great fun partially cause I didn't have a clue what I was doing.