How to not lose?

[I Have Low Eyes]

Basically I tried CK2 a few times and epicly sucked. I am worse at it than other PDS games except hearts of iron. My empires always fall apart due to crappy inheritance. I don't really know what to do besides conquer neighbors and then fight rebellions.

I do understand some of the mechanics but just suck at CK2 and would like giving it another shot.

 

[KamikazeKrieger]

So apart from the usual read guides and watch tutorials, what helped me by far the most was just watching other people play the game, like Arumba for example, observe how and why they do the things they do.

As for Inheritance you could go either the "disposal" route and kill of everyone that has a claim or might inherit apart from your desired heir, or just marry everyone off matrilinially. Its the same effect only one heir left and no trouble with the realm breaking apart.

 

[Mike Louis]

It's definitely helpful if you read and watch the various guides / Let's Plays for the game. Also plain ol' trial and error can be beneficial as you can see why everything is happening. Once you learn stuff like how the marriage, vassal management, and inheritance mechanics works, playing CK2 will become easier. Unlike other PDS games, CK2 is about building for the long term, more about the marathon than the sprint or 50 yard dash.
One the biggest things in CK2 is knowing when to make your move whether in the smoke filled backroom or the chaotic battlefield. Using myself as a example, in my current game using the 769 startdate my realm is located in the Levant region of the Middle East. From the start, I know that I need to build up both my infrastructure (buildings) and my armies (retinues and levies) as I'm in a rough neighborhood (Abbasids, Byzantines, and in my personal mod the Scythian Amazons) in which the other Middle Eastern powers will pounce on me at the first sign of weakness. Therefore until my retinues and levies are fully built up, I keep my head down assuming what I call the "Eye of Sauron" stance waiting for my potential enemies to weaken internally before I decide to go for the kill. Even then I'll hire mercenaries to do the dirty work before committing my own retinues / levies. There's a reason why Edward Longshanks in Braveheart said "Arrows cost money...Use up the Irish, the dead cost nothing!"

 

[Sonmi]

1. Get rid of gavelkind as soon as possible.
2. Growing is important, but so is keeping your vassals in check. Don't let them become too powerful.
3. If you decide to go massive, your vassals will become stronger than you. If you own Conclave, make some of them extremely powerful and stick them on the council.
4. If you own Conclave and grow to empire-level, use council-enabled war declarations. It might be a pain in the ass to declare some wars, but at least you won't have your entire realm rebelling for more council power.
5. Pace yourself, defensive pacts can now spell your doom if you expand too fast. Prioritize enemy rebellions, they can't join coalitions and are thus easy pickings.
6. Learn to use intrigue to your advantage. It can save you from plenty of situations.
7. Land as many dynasty members as possible.
8. Never trust a Venician.

 

[Dadoverde]

9. An infidel neighbour too powerful? Make a diplomatic friendship.
10. Still worried about gavelkind? Ok, one-son policy. ;-)

 

[Legionary Guard]

11: Try to keep a temple (If Christian) in your personal demesne in case you need to disinherit a crappy son on the cheap.
12: As an alternative to getting rid of Gavelkind, keep Gavelkind and only bother getting bastards, legitimizing the one you want to be your heir.

 

[Sergeant Flutter]

CK2 is a very slow paced game. Your realm is falling apart because you're conquering too quickly and not setting up sound Administration.

This will cause peasant rebellions, vassal rebellions, and weak defense against external invasions.

Also, not properly keeping your realm organized can lead to various titles leaving your realm, Claim Wars, and whole bunch of awful things.

 

[sumdood]

CK isn't like your typical strategy game, where it gets easier as you get bigger--it's the opposite. Taking land is the easy part, keeping your realm together is the hard part. You said you were trying to keep together your empire, so I'm guessing you have a large realm, which is difficult to maintain. I'd recommend starting small to get the hang of the game first, but not too small or in an area where you would be gobbled up easily. One of the duchies in 1066 Ireland is a good start, you're small but on equal footing with your neighbors.