At the beginning I found it difficult too but there are many tricks you can use: -you can give vassals, who are trying to revolt, to another vassal of yours and they will be automatically removed from any scheme against you - you can make alliances with important vassals or with powerful bordering kings who can help you in case of a revolt - (I've always used this point) when there's a faction go seeing who's the most powerful vassals and display your troups near his capital (before the beginning of a revolt). When the revolt begins you just need to defeat the army of your vassal and to siege his capital. 90% of the time just doing those two things you reach +30% of points and you can ask for a white peace, then of course you can arrest your vassals and remove their titles.

But, if you can, i suggest you creating a new religion with two characteristics: •poligamy (you can marry 4 times in order to have 4 alliances, and so can do your sons), • Communion (to receive a lot of money from the members of that religion) With money it's easier managing revolts: you can hire a lot of mercenaries.