Fuel off
Mixture cut off
Close throttle
Master off
mags off
Carb heat off
Attempt to dive, and or slip for incombustible mixture and extinguish the fire
If no worky, dive at max flap extension speed with full flaps and full slip for a landing field. On the Cessna, I might even flip the master back on to add in full flaps.
Why close the throttle? Wouldn't through the engine be a good place to process the flames?