Proper fire prevention should include paying attention to all of these, EXCEPT:

Pre-trip inspection: Make a complete inspection of the electrical, fuel and exhaust systems, tires and cargo. Be sure to check that the fire extinguisher is charged.
Enroute inspection:
Check the tires, wheels and truck body for signs of heat whenever you stop during a trip.
Follow safety procedures:
Follow correct safety procedures for fueling the vehicle, using brakes, handling flares and other activities that can cause a fire.
Monitoring: Check the instruments and gauges often for signs of overheating, and use the mirrors to look for signs of smoke from tires or the vehicle.