As a nation, using the economy tab, keep maintenance at 15% or higher, and make sure that you begin focuses that give you political power first, and get Written Laws and High Taxes. After this get advisors using funds that you get from decisions/national ideas, You should start with a Treasurer, Then a Merchant, Then a Farmer. The first two will aid your economy, while the farmer aids your population growth, helping yourself grow a manpower pool. Along with this, if you are the teutonic order the game is easier as the decisions and national focuses are OP. Following this spending into getting more income per day, Make sure you only keep 100 in your bank at all times. Because a bank robbery can screw over all your funds and make them disappear. Now that you have gotten quite a bit of money and or are making money, you should begin the buying of swords to help grow your local stockpile, and then begin to go into the industrial focus trees afterwards. Hoped I helped with something!