Match the pot to the size of the cooking element. The pot should just cover the element. If the pot is larger than the element, more energy will be required to heat the pot. If the pot is smaller than the element, energy is wasted.
Get rid of those garage sale pans. Pans that are bent or with
deformed bottoms don't make full contact with heating elements
and require more energy to heat up.
Ensure lids fit properly and, when possible, keep them on when
cooking. This traps the heat in and allows you to lower the
temperature of the element. Doing this can save you up to 20% of
the energy required to cook your meal and your food will cook
quicker and more evenly.
Keep the drip pan under the element clean. Don't line drip pans
with aluminum foil, this may reflect heat away from the pot and
damage the elements.
Use an electric kettle to boil water instead of using the stove
top which is less efficient.