When boiling water in winter, don't turn on the hood fan right away, so all the heat doesn't escape  the house.
 
Coil the  water heater inlet line around the vent pipe for your clothes dryer to pick up some of the wasted heat, so you use less fuel to heat it to temperature
 
Barbecue more in summer to keep heat out of the house and cut down on air conditioning 
 
Fertilize the deciduous trees on the south side of your house, so they block out more direct sunlight in summer and, when they lose their leaves in winter, more sunlight gets in.