Here are some ideas for saving energy on air conditioning:
Set air conditioning at 78 degrees or higher.
Close drapes on the sunny side of the house.
Keep windows open at night and close in the morning before it warms up.
Add bamboo or vinyl blinds outside sunny windows to block heat transfer.
If inside draperies are used to shade the window, there is still considerable heat buildup in between the drapes and the window. If nothing else does the job put aluminum foil on the window.
Plant trees and shrubs to shade south and west-facing windows.
For a quicker solution add a lattice screen with a vine plant on it. Make sure the screen is far enough from the house wall to keep the plants off the building.
Self-adhesive window tints can be cut to fit most standard windows.
Also available are movable shades in dark-tinted mylar that roll up like a fabric window shade.
Open a window high on one side of your house and another one low on the other side. This will promote natural cross ventilation. Do this in the cool of the early morning or evening.
Use the kitchen and bathroom exhaust fans to help pull cool air through. The furnace fan helps circulate cool outside air around the house.
Keep windows closed during the heat of the day.
Avoid cooking indoors to keep oven and stove heat from contributing to the home's temperature.
Re-schedule baking and broiling to a cooler time of day. If you have to cook indoors, use the kitchen range hood to help vent away hot air.
Keep lights off when possible. A 100-watt standard light bulb puts out about 90 watts of heat and halogen torchiere uplights are equivalent to small space heaters. Change as many lights as you can to cooler operating fluorescent and you'll reduce the lighting-related heat in the house.