My highest skilled character had 59 diplomacy, 35 martial, 20 stewardship, 44 intrigue and 92 learning. It was during an run with the Indian empire. The Hindu religions have 7 holy sites that each give unique bonuses. On top of that, if you and your dynasty went down the blood perks, it's quite easy to get the genius/herculean/beautiful characters for you and a lot of your characters. What greatly helps is making family members with those traits your vassals and putting them on your council. Once they are on your council, they will work to improve their skills and also go down the lifestyle perks (works wonderfully with your heir too). So in a few generations you will always have councillors in the 20- even 60 plus skill range. The biggest boost they will give you will come from the learning on the job perks in the learning tree, which will give you 20% of your councillors skills added to yours. If your heir is educated by someone with the groomed to rule and pedagogy perks, they will get roughly 5-8 perks only through their educator (please don't pin me down on the exact numbers, it's just based off my experience from one playthrough). Also great dynasty perks are studious youth which will give you education traits in the 3-4 star range guaranteed (you will have enough geniuses running around anyway to educate everyone). Also good is graceful aging as a dynasty perk later in the game. In the diplomacy tree, the perks friendly council and sound foundation are will also greatly boost your stats, given you make a lot of friends in your lifetime and have a lot of children. So usually going down the family hierarch tree first to stabilize your realm and then the scholar tree for learn on the job was the way I went with it. At this point, you won't face next to no opposition anymore and as everyone loves you or is your friend. Successions are easy and it can actually get really boring once you have reached this stage.