1. Find a medium-power country that's somewhat smaller than yours. For example, Bavaria.
2. Get a royal marriage with them, and avoid marriages with other people for the time being.
3. Wait until they have low legitimacy or a bad heir, and make sure you still have a royal marriage.
4. Fabricate claims with a spy if you can, claim throne if you can't.
5. Attack as soon as possible, claims to thrones have an annoying tendency to be lost rather quickly.
5. Shoot all their guys.
6. Force a personal union in the peace.
7. IMMEDIATELY shower them with gifts and nice treaties! If your monarch dies with relations between your countries still low, the union will end. THIS IS
THE WORST POSSIBLE OUTCOME!!!
8. Keep relations between your countries very good, and keep your prestige above zero. Negative prestige on ruler death ends the union. Legitimacy might have some effects too, but I'm not certain.
9. If you have fewer regiments than your 'partner', they will send you insults every month whilst they are at peace, in order to reduce relations and get out of the onion. This is why you must only try to take the thrones of weaker countries.
10. Each time your monarch dies, there is a good chance that you will inherit the lesser country. If you inherit, you win all their provinces instantly.
11. If/when you inherit, you will gain cores on all the core provinces of the former state that are in your culture group. If both of you are in the Empire, you will get the cores anyway, regardless of culture.
12. If you have had a union for 50 years, you can 'integrate' the other country. This is like inheritance, but you never get any cores. This is most useful if you have a union with someone outside your culture group. Otherwise, it's not really worth it.
13. If you have a royal marriage with any country, you can sometimes get lucky and form a union with them by chance, without claiming the throne and going to war.
14. If you are
really lucky, you can inherit a country that you have a royal marriage with, without even going through a personal union. This happens for the AI more often than it does for the human. Often this is more of a curse than a blessing though, since the inherited land tends to be miles away from your territory and with a different culture. I inherited Scotland as France once, which was kind of cool since this was back in old Vanilla EU III when inheritance automatically gave you cores regardless of culture. Also, there was no such thing as colonial range and 'fabricate claims' would create a free core, but that's a different story...
15. If the union does break, you get a 'restoration of union' CB on the traitors.
16. If you inherit some land you don't want, you could consider giving it to another country or releasing a vassal.
17. Snakes can sometimes be dangerous, especially to young children.
18. If you end up in a union yourself, don't form an alliance with the master, and just insult them until relations are below 0. Player countries cannot be inherited at all, even in multiplayer, so being stuck in a union is largely just an annoyance for you.
