I have no fucking idea what's going on in Crusader Kings II. Apparently I'm supposed to press de jure claims on something and have no idea how. One of my vassals was being a punk, so I started a plot to revoke his something or other. I took out his army because mine was way bigger, then I sat outside his city for several years because apparently there's like 600 people defending it, yet his army only had like 50 or so and I slaughtered the crap out of them. He supposedly leads his army into battle every time, but no matter how many times I fight them I can't kill him apparently.
And then every single member of my family starts bitching to me about how they want a wife so I hook them up (seriously I arranged like 12 marriages), now they're bitching about wanting kids. Do I have to fucking show them where to put their dicks?! I don't even know. Now I've got like 20 people who want to be councillor, but according to their stats most of them wouldn't know their arse from their elbow.
I don't even know.
If you haven't gone through the tutorials I highly suggest you do so before continuing on. Also, the count/duke/king you play (although playing a king first off is not something I would recommend) can make the game much harder if you don't know what's happening. The best place to start as a beginner is either the Duke of Dublin, the Duke of Munster or if you're not a fan of the Irish, the Duke of Apulia.
Pressing de jure claims means just go and attack that province and take it for yourself because, by law, you should hold that province. Depending on who you are playing as or what titles you hold you might get de jure claims on provinces that aren't yours but should be because you are the Duke/King of that duchy/kingdom. It's like if I was the King of England but the Count of Essex was independent, I would have a de jure claim on Essex because technically that belongs to the Kingdom of England.
Don't worry about trying to marry every single family member off, if they keep bothering you with events, just pick the first person you see that's fertile. The main people that you should worry about in regards to marriage is your children and grandchildren, these are the heirs of your dynasty and you need to keep the line going to keep playing. The thing about people wanting 12 children or being councillors are personal ambitions, most of the time they can be ignored because you can't control how productive couples are (well, you could find a better wife/husband for him/her but really, if it's not someone in your direct line, who cares). Similarly, some people just don't have the stats to be council members despite what they want to be, don't bother with these requests.
Join Steam chat next time you play and ask questions, there are quite a few of us that have the game now and I'm sure we would be able to answer your questions. Also, if you have lots of time to kill read this:
http://forum.paradoxplaza.com/forum/showthread.php?589469-GUIDE-In-depth-Guide-to-CKII (you will need an account to view it though).