If you can complete the first scenario (Mongol Conquest) before the year 1214, you will unlock a fourth scenario: World Conquest!
Ss soon as you start decree some new policies. Normally I do 50 0 0 50 but another good thing is 50 0 15 35. After acquiring enough money to last a few years, set everything into farming. Give it a bit and the food stockpile will rise like nuts. (the difference between herding and farming is that herding you get about 700-900 food every season and farming takes a while to get food but when you do and it gets really high its 1'000-2'000 food each season). After you have 3'000+ food set everything into construction to earn some money. Give it a bit and you will start getting 1'500 gold each season. The max amount of money is 9'999.
When Merchants come into your area, make sure there are both Chinese and Ughire. Buy as much silk as you can from the Chinese and sell it to the Ughire. Because of the price differences you end up making money.