I wouldn't call this an exploit, more like a funky mechanics. so what to need is a fast army (at least 5.0+ campaign speed) and to be a war with someone.
step 1: using your speed find and fight a weak enemy lord (farms Tactics)
step 2: always release the enemy lord after battle but capture their troops. (farms Charm)
step 3: once your prisoner count is reaching its limit, head to a ally/neutral settlement and sell your prisoners (farms Roguery)
and bam, you're done! I got over 200 Charm and tactics and 100+ Roguery by mid-game by this method. a few suggestions I'd like to give are that it's better to have an army of infantry with horses in your inventory rather than cavalry since you will loss troops in the process. if your speed comes from the horses of your troops rather than in your inventory you'll constantly need to buy horses to achieve 5.0+ speed. also do NOT go to deep into enemy territory looking for lords since you could be surrounded and captured. stay close to friendly/neutral settlements. also not an exploit because you can only feasibly do this if your side is not losing; letting lords go means they can come back with another army, albeit a weaker army then before.
step 1: using your speed find and fight a weak enemy lord (farms Tactics)
step 2: always release the enemy lord after battle but capture their troops. (farms Charm)
step 3: once your prisoner count is reaching its limit, head to a ally/neutral settlement and sell your prisoners (farms Roguery)
and bam, you're done! I got over 200 Charm and tactics and 100+ Roguery by mid-game by this method. a few suggestions I'd like to give are that it's better to have an army of infantry with horses in your inventory rather than cavalry since you will loss troops in the process. if your speed comes from the horses of your troops rather than in your inventory you'll constantly need to buy horses to achieve 5.0+ speed. also do NOT go to deep into enemy territory looking for lords since you could be surrounded and captured. stay close to friendly/neutral settlements. also not an exploit because you can only feasibly do this if your side is not losing; letting lords go means they can come back with another army, albeit a weaker army then before.