There is no one-best-recipe.

Your vassals should never have too many titles - in this case they will have power to singlehandedly overthrow you and usurp your title or make you to lower crown athourity or taxes or levy size. And be sure - there will be time when they want it.

Also don't give titles to someone who hates you - in this case make them your vassal's vassal - this is a suitable solution for unlanded sons or brothers. It also makes them harder to raise war for your crown, because they should firstly became duchies, and this involves war with their liege, whom they may hate no so strongly.

Give titles to ppl who have Content trait (+50 relations), to someone with same sins and virtues as you, also try to make your king as good as your can - vurtuous, kind, just, prestigeous, piuos.

Look for vassals' background - dont give land title to priests and mayors - they will have "Wrong goverment type" penalty.

Respect - is everything. You can fight with rebel vasslas, but not with all of them at the same time.

Well, maybe messy, but here are some tips) Hope it will be helpful.

There is no one-best-recipe.

Your vassals should never have too many titles - in this case they will have power to singlehandedly overthrow you and usurp your title or make you to lower crown authority or taxes or levy size. And be sure - there will be time when they want it.

Also don't give titles to someone who hates you - in this case make them your vassal's vassal - this is a suitable solution for unlanded sons or brothers. It also makes them harder to raise war for your crown, because they should firstly became duchies, and this involves war with their liege, whom they may hate no so strongly.

Give titles to ppl who have Content trait (+50 relations), to someone with same sins and virtues as you, also try to make your king as good as your can - virtuous, kind, just, prestigious, pious.

Look for vassals' background - don't give land title to priests and mayors - they will have "Wrong government type" penalty.

Respect - is everything. You can fight with rebel vasslas, but not with all of them at the same time.

Hope they will be helpful!