See (long and boring) example from my last finished game of a random turn notes
Wow, now that was something Unfortunately I don't have the patience to do something similar, so usually small mistakes here and there lead to big problems at the end...
Im too lazy for good notes. I tend to use something like AutoHotKey to create macros then update them. Such as, the "important provinces" part of WraithLord's notes would be something like Ctrl-Alt-C for CHECK which does a # then types in the province number. That way I can use it to make sure I roll thru each one and add recruiting. Then I just edit the macro to add each new important province.
I could even change the macro to do the recruiting so that one keypress does it all in 100 provinces but kindof kills the game for me.