It may not be feasible to replace all of your incandescent bulbs at once; prioritize the rooms with the greatest lighting usage.
If you turn a CFL on and off frequently, it will not meet its rated life expectancy. CFLs work best if they are left on for at least 15 minutes each time they are illuminated.
Light your landscape, sans energy costs, with solar outdoor lighting. Solar lights collect energy from the sun during the day to provide illumination at night.
Switch off that overhead room lighting and opt for a desk lamp or lower-wattage lamp.
An easy way to increase energy savings is to use fluorescent bulbs when possible. Make sure you are using the correct wattage, and keep your light bulbs clean (dirt absorbs light).
Fun fact: If everyone in Ames replaced five incandescent bulbs with CFLs, 40 million pounds of CO2 could be eliminated from the atmosphere.