I have rarely been in financial trouble in MTW, but once in a while, I get hammered. This formula has proven fairly successful and saving me from running out of money when my back is against the wall. Feel free to post your own techniques!

1. Whenever you have a real surplus of money, find an out of the way province and build an expensive but unecessary building. Chapter-Houses are useful, and buildings for making spies or assassins. When you are running low on cash, destroy the building and you get a few hundred florin.

2. Re-organize your army and disband excess units. Always go smaller armies of more efficient soldiers. Masses of cheap troops can be as draining as more expensive units if you are not careful. Peasants are useful garrison troops for completely safe provinces, but after a while, some provinces don't need a garrison at all.

3. You will be shocked at how easy it is to forget to keep your governors' acumen levels up. Once in a while, like every 3 turns, check your governors, and replace those with acumens below 5 points if possible, and never let a men with less than 4 rule a county (unless he has a +acumen virtue that will grow or negates the loss by having a +% to agricultural or trade output)

4. Raiding is useful. If the enemy (or a neutral) has an exposed province with lots of buildings, take and destroy all the buildings, then retreat. That could get you 2-3,000 florins in a pinch.

5. If you are in a bad state, retreating to shorten your borders is a last-resort which has saved me on many occasions.

6. He who rules the seas, rules the world. Always put your priority on your navy and tradelinks if possible. Keep a large fleet on hand to prevent enemy from cutting your trade routes. Try to keep your fleets at a minimum of 3 ships each to give you a good chance of surviving attack, even with weak ships. This can take time, but it pays off greatly in the end.