I have to say that the best advice is just to devote a lot of time to figuring the game out yourself, but after a long stretch of failed attempts I finally succeeded with Poland. I was doing decently for the early game, but I had a break-through that allowed me to run rough-shot over everyone in my way. I was told, nearly the first tip ever given to me, not to mint money because inflation was horrible. Well, with that in mind I seemed to always go broke and have to take out loans and I was never ever able to field a respectable army that could do more than harass any nation worth their salt without getting some crazy ass losses per year.
Well, I finally realized that if I compared how low my inflation was to the computers it was like we were playing two different games. The only nations that had low inflation were the single state traders that just mind their own business the whole game and get stupid high research levels. Needless to say I didn't feel like playing as such a pacifist, I then looked and checked the inflation rates of every decent sized or large nation in the game and they had huge inflation rates, yet they were doing very well for themselves. I then loaded up a game of one said nation (France) and found out that it didn't cost that much more to build and recruit things than my tiny inflation having country. Needless to say I felt like I'd been cheated.
After that I put my army and financial needs first, then, after all is said and done I keep my money minting level to the point where I'm losing plenty each month, but is manageable and don't worry about the inflation. After I did that I was able to expand so rapidly that I had to struggle to keep from becoming bad boy. I went from nearly caput to going into a golden age.
Needless to say, telling people to not mint money and that inflation is the boogeyman is probably the biggest handicap I could give someone. If you are going to be fighting wars have a damn army already! I don't understand how people can play a game where they don't mint money at all.
Btw, it is the very late 1500's and my inflation is 9%. France is around 25 or so, and it is even higher for the Ottomans.
^ Said inappropriate priorities are what kept me from having a successful Russian campaign. You just can not worry about that crap until you solidify your place. Those steppe tribes are ruthless and could care less how high their inflation has to get to field those 25 thousand strong cavalry armies, while you are fielding 2 little armies of 5 thousand in order to balance your soon to be conquered budget.
Yes? No? Horribly incorrect? I'd also like to hear of some others...