I was unconvinced whether to buy it (and I'll probably get it through Steam because that would be much easier for me in the long-term, 'free' DLCs or not), but then I played the demo and loved it.
I've not really played CK1, so not very experienced, but I think I'd like to start as Duke of Bohemia, and solidifying myself as King of Bohemia, and also Duke of Bohemia and Moravia. I'd also try to institute elective succession, so I could choose my successors (seeming as I would hold the two ducal titles in the Kingdom). I'd spend probably a few decades improving the lands, getting the feel of the game, and so on. Then it'd be time to face outwards .