Currently playing as Shimazu - looking for suggestions for my 2nd campaign

Game got REALLY hard after the realm divide when all my allies turned on me. It took about 5-6 years for me to consolidate and I think the rest of the game will be a breeze - sinc my economy is finally back to normal after l;osing all my trade partners and I own the map south of the 2 mountain passes just north of Kyoto.