These are the vehicle-related changes I've implemented with the goal of improving fuel economy:

1. Pump tires to 42/40 psi (front/rear)
2. Install block heater
3. 0W20 synthetic oil
4. Shell gasoline

The block heater helps a lot for short trips (my commute is 10 mi). There have been times where, after the initial ICE startup, my car has gone immediately into EV mode after pulling out of the driveway. That never happened before unless I had driven earlier in the day and very recently. It's nice to have averaged 40 mpg after only 1.5 mi.