I have almost 1000 hours in Bannerlord (rookie numbers, I know) and yet sometimes I get told something or discover something that I should have known, but I for some reason missed.
I'll give you a couple of examples of things I only learned recently. For a lot of players this is basic info, but I bet there are others who didnt know this. And please, give your own tips, I dont care how obvious they might be:
1: When talking to a lord/lady to convince them to join your faction, any progress you make gets saved. So, if I need 4 successes to convince them, and only get 2, those two succeses get saved. So if I wait a week and try to convince them again, I start at 2 successes already. You have to wait about a week or two, or else they'll just say that you tried to convince them before and they havent changed their mind. If they do, just wait longer and try again.
2: I never used to visit taverns, because I just check if theres a wanderer there from the Town menu and talk to them if I want to. But if you visit the tavern you can ask the Tavern keeper if there are other wanderers who have passed through. You'll get their names and they show up in the encyclopedia so you know what they are good at, and where they are. It costs 2 denars per tip.
3: Not only that, you can also ask the Tavern keeper about who rules the town, and you get encyclopedia info on their entire clan, and every member! Very useful when looking for a wife. it costs 500 denars, but if you have plenty of money, its worth it IMO.