Sorry if these have been posted already:

Campaign:
It doesn't work well to try to have Tier 3 or 4 buildings in all of your settlements as these can be very costly in terms of squalor, food, or public order. Since food can be imported from other provinces, specialization by province is possible e.g. military, financial, etc. The beta 3 patch reduced some of the higher-level building penalties somewhat.

The strategic overview also has overlay toggle buttons to see: population growth, wealth, public order

If a third party is blocking the port of one of the enemy settlements you wish to take, you can place your army in the combat zone and wait for the third party to initiate an assault. Then just decline to take part. The third party is defeated and runs off and you can assault the settlement.

Great way to move troops really far: Have a forced march "relay" with your generals. One with bunch of troops force marches to merge with another general that has no or little troops. He takes them the rest of the way.

Battle:

Fun: hitting "Insert" or clicking the cinematic camera button after selecting a siege weapon allows you to control its shooting personally.

The "N" key is by default how you zoom from far away and how people are able to see the zombie faces. Doesn't work in cinematic mode, it kicks you out of cinematic mode.