Gas and electric ovens can get very hot while baking. That heat will stay inside the unit as long as you keep the oven door closed. When you are down to the last 5-10 minutes of baking time on your next dish, turn the oven off. Your food will continue to bake with the residual heat already inside.
For those of you who have an electric stove top, consider turning off the burner about 5 minutes before your food is done. There is plenty of left-over heat on the stove top to continue cookng your food. This doesn't work as well for gas burners.
