1. Recover manpower (especially if you are playing 5.2).
2. Prepare for the next war.
3. Fix your finances.
4. Check to see what all your neighbours and biggest rivals are doing (their missions, wars, allies). Spot those who are weak (no or weak allies, in a war they are losing, close to you, with provinces you want, etc).
YOU WANT CONSTANT WAR: PLAY RUSSIA
If you want constant war, play a Russian minor (obviously you will want to form Russia). Trust me, you will be begging for some peace (not that you can't handle them, especially after you form Russia, but there will come a point when you will just want to relax a bit). First you face the Golden Horde, then you border Nogai and Qara Koyunlu, then Kazakh, then Timur, then Chogatai, then the Oirat Horde, and finally the Mongol Khanata (who are usually occupied by Ming, with Ming never accepting peace and thus you can't occupy their territories and are in constant war)!
And all these, while trying to take back your provinces from Lithuania, which is weak but allied to Poland - they are easy to beat but the problem is that you have to split your troops between the western and eastern fronts. If you have truce with the hordes you need to be fast to move all your troops to the western front, defeat POL-LIT and move them back to the eastern front, while making sure you don't lose much manpower.
Then you get the mission to get back Finland from the Swedes (which will grant you cores to all provinces - so sweet) but the problem is that although weak, they are in PU with DEN-NOR so the above applies to them!!!
