[curtadams]

The most valuable trick is that the AI responds to what your strength was in the *previous* turn. So if you move from province A to province B you will often catch a defeatable force moving into B. The Dom2 AI was ridiculously easy to fool - it's better now but still often beatable. I do find that AI is prone to gang up on you and that's hard to deal with. I just barely won a game when 3 AIs jumped me. A high independent setting and lots of mountains help.

Another trick is that the AI is incredibly defensive about its home province. If you can get an army on it, all units in adjacent provinces will attack you every turn. That pretty much locks down an AI; you'll still have to deal with armies already in your territory but you usually won't see more. Of course the army must be very strong and if you can't keep an adjacent province any retreaters die.

As mentioned above, PD helps a lot. A large army seems to discourage the AI from attacking you but it's not perfect.