I have the general thread up but it's good to have a separate thread for anyone who's interested in this specific topic. I always go over EDCT and EDA to figure out every last detail for traits and ancillaries. Because there's a lot of details, for efficiency, what I'll do is only mention the actionable information. This information is mod specific. There are overlaps but vanilla requires a different way of handling things.
Generals/Governors
-The first step before raising is filtering. House rules don't allow for the suicide of bad characters but there's nothing stopping you from giving all the risky and mundane assignments to bad characters. Bad traits may start out good but self perpetuate and are bad in their final form. By far the worst character trait to have is alcoholism, it reduces all the character's skills and is bad for everything. Sobriety is slightly bad but alcoholism is so bad that I consider sobriety a great trait since it insures against alcoholism. Bad traits other than alcoholism have salvage potential. That said, some characters have so many bad traits that they might as well be an alcoholic who's not worth salvaging.
-Religion cuts influence and command, the management boosting traits other than stern cut influence. Keep in mind influence isn't just useful for governors, it's just as useful for generals because it increases command radius and bodyguard size. The best salvage for characters with influence reducing traits is to have them govern cities near your capital. You likely won't need the public order boost from influence.
-Superstition cuts management and morale. The best salvage for that and management reducing traits is for those characters to govern remote cities. Remote cities don't make much money because of corruption so you're not losing that much from management loss anyway. Alternatively, such characters could be generals. Morale loss wouldn't be optimal for a general but it's also not the end of the world because morale loss is only 1 and most units have a base morale from 10-20
-Unless you have more pressing concerns, the large town level temple of Jupiter is the most valuable building you can construct. It gives you full access to get any of the Roman priest ancillaries, it also has a 10% chance of adding to the disciplinarian trait every turn. All of this and it only costs 3 turns. Take note that a character can not have moved from the city that turn to get the chance.
-Everyone has difference preferences for what they like on a general. For me, mobility is king. Not moving from a city with a large city level barracks has a 10% chance of spawning a quartermaster. If a general has at least 4 command stars, recruiting infantry has 3% chance of spawning a drillmaster. Retraining doesn't count but peasants and missile foot units still do. Recruitment stacks with 0 turn recruitment meaning you have 9x the chance if you recruit 9 units. Ending turn with a character with close to no movement in barbarian faction lands has an 8% chance of spawning an intrepid explorer. Rebel barbarians count too. Ending turn outside of a city with close to no movement has a 10% chance of adding to logistics skill if the character has at least 3 management.
-There is only one consistent good governor trait which is the bureaucrat trait. Training a unit with high/VH tax adds to it. The probability also stacks 9x if you were to recruit 9 units. Building completion on high/VH tax works as well but is relatively infrequent.
-Building a governor as a good taxman or bad taxman is up to you. Good tax is more tax more unrest, bad tax is less tax less unrest. Which gets the point is determined when a building is completed. High/VH tax and a non rioting population adds to good and low/normal tax with a happy population adds to bad.
-Completing a mine adds a point to good miner. Keep in mind, mines can't be destroyed and characters eventually die so this trait will eventually be extinct. Also, the trait maxes out after 8 mines built.
-Keep in mind some traits require multiple points to move up to the next level so you might not notice gains right away.
-General who are militarily successful gain many influence traits. I used the umbrella term because there's lots of ways to be militarily successful. Retiring these generals to govern is an idea because then the new generation of generals have the chance to take over and gain these influence traits.
-Family members vs generals. This is situational but a general tip is to put family members in remote areas if they're not needed elsewhere. Family members beget more family members. When your empire is larger, it saves a great deal of travel distance since you can only recruit generals in home regions.
-If the father is in region, the son or son in law spawns in the regional city. If he is not, the spawn is in your capital which can be moved. This gives you a small measure of control for where to put the spawn since you can tell when sons come of age.
-Mine income is your primary source of income. Silver mines give 5K, gold mines give 6.25K, cities with both give a massive 11.25K. Characters with high management are suitable for mines near your capital. Far from your capital, corruption eats a large portion of the income. In this case, characters with high law are suitable.
-This isn't character related but I still want to include it. Because of the larger map size, only a small radius gains the benefits of being close to the capital. The most central location isn't necessarily the best. An alternate suggestion to central could be high culture penalty areas, for example, say you've taken all the areas of the western Roman empire and rebuilt them. Say this has taken you a long time and the east is fully built and you can't rebuild there and are stuck with the culture penalty. In this case, moving the capital to Byzantium could make sense. Another idea is to centralize your capital between your best mines.
-Adopting a family member creates a chance for the of age brothers to pick up bad traits. Check your family tree before accepting. Man of the hour is risky because AFAIK, the adopter is random. It would be of great help if anyone knows a way to tell who adopts the man of the hour.
-When you end turn with treasury over 150K, you have a chance for bad traits from characters who don't move from their city.
-Academies give good traits and ancillaries but this is probably taken as a given.
Other
-Admirals ending turn with close to no movement have a 5% chance to gain a navigator. Personally, I find this bad instead of good because I mostly use ships for transport and any traits or ancillaries on admirals prevents them from merging. If you're not transporting and want to build a war fleet, shipwright built admirals have a 4% chance of a shipwright, and dockyard built admirals have a 20% chance of a seamaster.
-Each higher level of forum creates a better assassin. It doesn't matter for spies and diplomats.