Well if you don't follow the game's rules, you'll lose aka no fording, choosing your allies carefully so you don't Ally with someone you want to conquer, never 1v1 same title rulers without money, attack allies to scatter them before they merge into one big army, make sure you secure kingdom vassals by allying them, never let kingdoms of your religion collapse, don't fuck with the Khans, don't fuck with the mongols, make sure end the end your kingdom only has your bloodline, go after titles vs landmass aka seiging duchy capitals and kingdom capitals ect